Fill Factor Analysis of Organic Solar Cell

Fill Factor Analysis of Organic Solar Cell Rashmi Swami, Rajesh Awasthi, Sanjay Tiwari Abstract Solar cell is a device used to convert light into electricity. It can be made by organic and inorganic materials. Its most important parameters are open circuit voltage, short circuit current, fill factor and conversion efficiency. This paper is based on the analysis of factors that affect the fill factor of organic solar cell using MATLAB. Fill factor is calculated using conventional organic solar cell model without series and shunt resistances and constant light generated current for two different cases –first using Exponential dark characteristic and second using Polynomial dark characteristic. We get for exponential V-I relationship increase in ideality factor n, will reduce the fill factor and for polynomial V-I relationship increase in m will increase fill factor. A large dependence of light generated current Iph on increasing applied voltage would cause a significant drop in fill factor. Increase or decrease in an additional factor would accordingly change fill factor. Dark current can be varied in two ways, one by varying mobility and other by varying injection barrier heights. In both the cases fill factor increases proportionately with . Keywords – Organic solar cell, fill factor, ideality factor, open circuit voltage, HTL, ETL. Introduction Bilayer organic solar cell as shown in fig. 1(a) is a device in which thin layer of organic material (donor and acceptor) is used between electrodes to convert light into electricity. This work is completely based on bilayer structure of organic solar cell as shown in fig.1(a) in which poly(9,9-dioctylfluorene-co-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4phenylenediamine) (PFB) is organic donor/HTL and poly(9,9-dioctylfluorene-co-benzothiadiazole) ( F8BT) is organic acceptor/ETL. Fig. 1(b) shows simplest conventional organic solar cell model without series and shunt resistances. Open circuit voltage, short circuit current, fill factor and efficiency are four important parameters of OSC. FF = Vmax Imax / VOC ISC When Vm= VOC and Im= ISC then (FF)max=1. For a good photo-voltaic device, all three factors FF, VOC, ISC should be large so that it can deliver large output power for the same incidental optical power. (b) Fig. 1 : (a) Bilayer organic solar cell structure. (b) Conventional organic solar cell model without series and shunt resistances. Simulation Model and Analysis of Fill Factor Two cases have been studied, one where dark characteristic is exponential like p-n junction and other where dark characteristics is polynomial like in space charge limited devices. 1.2.1Exponential Current Voltage Relationship – In this model, dark characteristic is assumed to follow exponential current voltage relationship and Iph is assumed to be constant. (1) where n is ideality factor and Vth is thermal voltage, Iph is light generated current, Id is dark current and I is net output current. Total output measured current can be written as a function of photo-generated current and dark current. (2) Output power of organic solar cell when it is operating at voltage V and giving current I- If maximum power is obtained at voltage Vm, , here assuming (3) Here y exp(y) is Lambert’s W function (4) and (5) At VOC net output current will be zero. At this condition eq. (2) will give (6) 1.2.2 Polynomial Current-Voltage Relationship In this case it is assumed that dark current depends on the applied voltage in the following manner- (7) Where K is constant and . (8) If photovoltaic is operated at voltage V and output current is I, output power will be- To calculate fill factor, one needs to find out the maximum power which photo-voltaic cell can supply. If maximum power is delivered at voltage Vm This will give, (9) and (10) At VOC net output current will be zero. At this condition eq. (8) will give (11) and (12) 1.2.3 Effect of Dark Current on Fill Factor – Simulation using 1D drift-diffusion electrical modeling of bilayer OSC in MATLAB is done. We obtained that the dependence of light generated current on the applied voltage means that fill factor would depend on it as well besides shape of dark characteristics. An estimate of variation of light current can be obtained by taking ratio of its value at short circuit and open circuit condition – At 0 volt, At VOC, i.e. The ratio is a measure of how drop in Iph with the voltage. This ratio can be written as – Thus shows an additional factor that would affect fill factor. As this factor increases or decreases, the fill factor should accordingly change too. Results and Conclusions Eq. (3) suggests that as ideality factor n is changed, keeping reverse saturation current I0 and photo-generated current Iph constant, Vm changes in such a manner that (Vm/n) remains constant. So Im will also be constant as it is a function of (Vm/n). From eq. (6) open circuit voltage is also changes with ideality factor n such that (VOC/n) remains constant. It follows from the above reasoning that (Im/ISC) and (Vm/VOC) will be unchanged if n will vary keeping the reverse saturation current constant. Hence as ideality factor n varies keeping the reverse saturation current I0 constant, fill factor of the device will remain unchanged. Though if open circuit voltage (VOC) assumed to be constant by varying reverse saturation current I0 as ideality factor n changes, fill factor will change accordingly. Assuming Iph to be 1 mA-cm-2, I0 to be mA-cm-2 and ideality factor n to be 1, open circuit voltage and fill factor come out to be 1.25 volts and 0.9 respectively. Taking Iph and VOC constant, the variation of fill factor with ideality factor n is shown in fig. 2. We get that increase in the value of ideality factor n, will reduce the value of fill factor Fig. 2 : Variation of fill factor with ideality constant n. open circuit voltage and light generated current are taken to be constant as 1.25 V and 1 mA-cm-2 respectively. Eq. (12) shows that fill factor is a function of m. Variation of fill factor with m is shown in fig. 3. For m = 1, FF = 0.25. As m increases fill factor also increases and approaches to 1. However, FF will become only 1 when m is infinity. In this case also, m is a measure of the sharpness of the characteristic curve. As m increases, I-V curve becomes increasingly sharper resulting in a high fill factor. For polynomial dark characteristic with constant light generated current we get that increase in m will increase fill factor which approaches to 1 Fig. 3 : Variation of fill factor with m. fill factor approaches to 1 as m becomes larger and larger. Simulation results revealed in fig. 4 show that light generated current Iph is a function of applied voltage, means FF would depend on it as well besides shape of dark characteristic. A large dependence of Iph on increasing applied voltage would cause a significant drop in FF. Increase or decrease in an additional factor would accordingly change fill factor. Dark current can be varied in two ways, one by varying mobility and other by varying injection barrier heights. In both the cases fill factor increases proportionately with as shown in fig. 5 and fig. 6. Fig. 4 : Dependence of light generated current on the applied voltage. and are the hole and electron mobilities respectively. and are the injection barriers at anode and cathode respectively. Fig. 5 : Variation of fill factor with for 0.1eV and 0.3eV injection barrier heights. Different points have been obtained by changing mobility. Fig. 6 : Variation of fill factor with for carrier mobilities and . Different points have been obtained by changing injection barrier height. References J. A. Barker, C. M. Ramsdale, and N. C. Greenham, â€Å"Modeling the current-voltage characteristics of bilayer polymer photovoltaic devices†, Physical Review B 67, (2003), 075205. D. P. Grubera, G. Meinhardtb and W. Papousekc, Modelling the light absorption in organic photovoltaic devices, Solar Energy Materials and Solar Cells, 87, (2005), 215-223. J. Wagner, T. Fritz, and H. Bottcher, Computer modelling of organic thin film solar cells exciton model of photocurrent generation, Physica Status Solidi A, 136, (1993), 423. Y. Roichman and N. Tessler, â€Å" Generalized Einstein relation for disordered semiconductors implications for device performance†, Appl. Phys. Lett., 80, (2002), 1948. J. C. Scott and G. G. Malliaras, â€Å"Charge injection and recombination at the metal-organic interface†, Chem. Phys. Lett., 299, (1999), 115. S. E. Shaheen, C. J. Brabec, N. S. Sariciftci, F. Padinger, T. Fromherz, and J. C. Hummelen,† 2.5 % efficient organic plastic solar cells†, Appl. Phys. Lett., 78, (2001), 841-843 B. K. Crone, P. S. Davids, I. H. Cambell and D. L. Smith, â€Å"Device model investigation of bilayer organic light emitting doide†, J. Appl. Phys., 84, (2000), 1974. P. W. M. Blom, M. J. M. de Jong and S. Breedijk, â€Å"Temperature dependent electron hole recombination in polymer light emitting diodes†, Appl. Phys. Lett., 71, (1997), 930. C. M. Ramsdale, J. A. Barker, A. C. Arias, J. D. MacKenzie, R. H. Friend and N. C. Greenham, â€Å"The origin of open circuit voltage in polyfluorene-based photovoltaic device†, J. Appl. Phys, 92, (2002),4266. B. Mazhari, â€Å"An improved solar cell circuit model for organic solar cells†, Solar Energy Materials Solar Cells, 90, (2002), 1021.

Analysis of M.I.A.s Paper Planes Music Video -- Music Analysis

There is one universal language: the language of music. Music has a special quality and ability to bridge both social and cultural divides. A proposed theory by Dr. Gray, Founder and Director of National Musical Arts’ BioMusic Program; describes music has been around longer than human-beings have. Music is the one thing human beings from various backgrounds can relate to. Every living creature would agree. Music is heard everywhere not just among humans, but in nature as well, through the twitting of birds, winds blowing, the soft sound of raindrops against a windowpane, the ocean waves moving back and forth and the hum of the ocean rushing in a sea shell. There is no escaping it; music lives in and surrounds us steadily. While there are countless songs which confer social or cultural consciousness, this paper will analyze and address the dynamics of M.I.A.’s â€Å"Paper Planes†, video. Stylistically, the paper will examine the artist point of view, the unique use of lyrical analysis and sound description in relation to its historical, social, political and/or cultural context. This essay will also trace the lyrical analysis and sound description of song and discuss how the elements (visually, sonically, and lyrically) interplay with the theme of immigration and/or violence. Known in the music genre as one of the â€Å"most provocative pop star of her age† (Sawyer, Pg. 1). Mathangi "Maya" Arulpragasam or M.I.A. by her stage name was born in London in 1975. At 6 months, her parents returned to their native land of Sri Lanka. Sri Lanka is an island which is located off the southern coast of the Indian in South Asia. M.I.A is considered one of the most controversial music artists of her time. Many agree that she has a unique way of com... ....com/wpdyn/content/article/2005/09/15/AR2005091500697_pf.html>. M.I.A., â€Å"Paper Planes,† 2007, [Lyrics], http://www.azlyrics.com/lyrics/mia/paperplanes.html Moraga, Cherrie, and Gloria Anzaldua. This Bridge Called My Back. New York: Kitchen Table Women of Color Press, 1984. N. pag. Print. â€Å"ONTD.com- Interview†, [2010] http://ohnotheydidnt.livejournal.com/45685085.html Reed, La Trina L. "La Trina’s Mixx Tape: A Literary look in." Los Angeles. 22 Mar. 2012. Essay. Sawyer, Miranda. "MIA: 'I'm here for the people'." The Observer 12 June 2010: 1+. Web. 25 May 2012. . Stetler, Carrie. "Violent references raise concerns in Sri Lankan pop star's 'Paper Planes'." Nj.com 8 Oct. 2008: 1+. Web. 20 May 2012. .

Leadership Empowerment Principle

The leader manifests an important role in each group or organization. He has the main objective of directing and leading the group towards the effective and efficient accomplishment and achievement of their tasks and common interest. He acts as the mediator and the source of power or command inside the group or organization for the management aspect of the diversity, individuality, and unity of each member for the processing and delegation of their different tasks and responsibilities. In general, the leader manifest as the core and central unit of the group making his the head element towards the realization and achievement of their common interest. In the contemporary perspective of group management, the aspect of leadership can be achieve and realize inside the group through different approaches each focusing on a certain aspect in the said aspect. Each leader is uniquely characterized by their specific style and nature of approach towards their purpose inside the group or organization. Every particular leader particularly focuses on a specific element on his leadership style which he views to be important and beneficial to the agenda of managing his group. This certain leadership style can be acknowledged through the realization of the elements he employs in managing his group and its influence to the effectiveness of their organization. In the aspect of realizing the leadership style for self-assessment, the author of this paper particularly examined specific points and elements for the assessment of his leadership style and the effectiveness of his approach. Based form the specific element highlighted in his approach, the author of this paper has realized the certain qualities in his leadership approach and the specific aspect he needs further development for greater effectiveness. From this assessment, the author of this paper has particularly learned the certain strength in his qualities namely the Chain of Command approach in leadership. In this quality, the author of this paper acknowledges that he finds certain strength in developing a sole authority for decision making and setting himself apart from the group for the chain of command. Through which that he is able to effectively manage his member and delegate the specific tasks necessary in their process. As also viewed in this assessment, the author of this paper also expresses interest in developing on the qualities of the centralized leadership particularly on developing group communication elements necessary for this approach. This leader particularly sees an opening for improvement in this aspect to develop an organization environment wherein he is a member but also the leader that directs everyone’s activities. Further on assessment, the author of this paper realizes that his style is best characterized as a partnership approach towards group management wherein aside from being the one with sole authority, he is also the supporter, coach and facilitator for each member’s activities. His style is to communicate and coordinate the activity of the group through imposing several tasks and responsibilities for each member particularly on the decision-making aspect. Thus, each member has their own tasks, responsibility, and specific decision taking part as co-leaders and members in the group. In particular, the author of this paper has the style of sharing the responsibility with the members and acting out as the supporter and facilitator for them. This style is also manifested by the author of this paper as part of his interest of developing a highly empowered leadership style in the group wherein the members are self-directed and has the full ownership of their tasks and most aspect of their jobs. The current approach of the author of this paper is mainly included as the initial step in developing the said approach wherein he is training the member to become independent on their responsibilities with the leader acting as the supporter and the coordinator for the organization tasks. This is mainly implemented on the interest of focusing more attention to the external forces and elements in the group as the members have already became self-directed and responsible for their group activity. Indeed, the leadership style and approach of each person is important as the effectiveness and efficiency of this aspect and the entire group process relies on the management and directing approach of their leader. Each style or approach has its respective element which is highlighted in the process towards the development of its effective application in the group. The effectiveness of this style relies on the characterizing factors and elements of the group, the issues that the organization must face, and the application approach of the leader which must be inclined towards the achievement and realization of the common good and interest of the entire organization. Bibliography Ohio Literacy Resources Center. Transformative Leadership: Leadership Development. http://literacy.kent.edu/Oasis/Leadership/over2.htm#lead. November 30, 2007. Â  

How To Make Your Content More Social Media Friendly

How To Make Your Content More Social Media Friendly Social media is key for  content marketing success.  Once youve put the work into producing a piece of content, you want it to catch fire and get tons of shares. All you have to do is blast the link across your social channels, and watch all the shares and traffic roll in. Right? Well, that isnt quite how it works. And if your social media content isnt performing, it could be because it isnt very social media friendly. Depending on how you look at it, social media can be a blessing or a curse. Sure, it is a great low cost channel for spreading your content, but it can also be a crippling scapegoat if you arent careful. You could but be publishing on social media regularly with little return on your investment, all with the appearance of doing great content marketing. Are your readers actually  sharing your content?  Are your really achieving the social traction that you expected or deserve? Is the good old hub-and-spoke model of content marketing actually working for you? Fortunately, the problem may be entirely your fault. You may just need to make some basic adjustments to make your content more social media friendly. The more friendly you make your content, after all, the more likely your readers will be to share it with their audience. Here are five easy ways that you can do just that. Want more people to share your content? Make it more social media friendly. 1.  Make Sure Your Content Looks Good On Social Media One of the first things that you need to do is to make sure that your content look good when it is shared on social media. This relies on  Ã‚  a small bit of meta-tag code that should included the HEAD of your html page. This code will provide instructions to networks like Twitter, Facebook, Google+ and Pinterest by telling them which image, title, and description to use when a post goes live. You can preview what your own link previews look like using this  handy debug tool provided by Facebook. There are several ways to ensure that your link previews always look great. The free  JetPack plugin  or  Yoast SEO plugin  for WordPress will make a "best guess" at what these link previews should include using data from the post itself. This is a good starting point, but may not offer enough flexibility for the power user. Tools like our own allow you to completely  customize your link previews, giving you maximum editing control. Recommended Reading: Best Practices Guide For Making Sure Your Posts Look Good On Social Media 2. Write Emotional Headlines Because They Get  Shared More One of the ways to make your content more social media friendly is to write headlines that are more likely to be shared with others. There are some very simple ways to do this. For example, our research has proved that headlines with more emotional value tend to get shared more with others. With millions of headlines in our system, we went through each one and calculated its  Emotional Marketing Value (EMV) – a rating that attempts to measure the emotional value of a headlines. What we learned was that headlines with a higher emotional value were more likely to be shared on line. The  Emotional Marketing Value Headline Analyzer  Ã‚  is a free tool from  the Advanced Marketing Institute that you can use to calculate the EMV of your own headlines. Can this tool predict shares? Maybe. Simply copy and paste your headline into the box and it will give you a calculated score of your headline’s EMV Score. After researching EMV, we thought a great tool would combine that research with other elements of headlines that drive shares, traffic, and search results. That's why we built the headline analyzer. Try this tool to write even better headlines. Write More Shareable  Headlines With Our Free Headline Analyzer The headline analyzer  will help you: Use headline types that get the most traction for social shares, traffic, and search engine ranking. Make sure you have the right word balance to write readable headlines that command attention. See the best  word and character length for search engines like Google and email subject lines, while also seeing  how your readers will scan your headlines. Try The Free Headline Analyzer Now Recommended  Reading: Proof That Emotional Headlines Get Shared More On Social Media 3.  Make Your Content  Easy To Share By adding simplicity to your page, you can increase the likelihood that someone will share your content, immediately making it more social media friendly. There are few simple things that you can do to make this more likely. Make Sure Your Social Sharing Buttons Are In The Right Spot Not long ago we took at look  at how the placement of social sharing buttons could  best influence social sharing from  our blog layout. What we found was that  the top/left side of the page seemed to perform the  best for most situations.  Because most websites load content on the left side of the page, and based on how people typically look through a site, it is pretty easy to see that the most noticeable place for this type of activity is in the top-left portion of the page.   Recommended Reading: What is the Best Placement for Social Media Buttons? Add Easily Sharable Content To Your Post Here at we made a simple plugin for our own use, and have  recently  made it available to everyone for free. This simple tool allows you to easily add tweetable content to your posts.  Ã‚  These boxes create important triggers that you can use to get your readers sharing content for you. Create beautiful boxes in your blog posts. #ClickToTweet Make Your Images Easy To Share SumoMe makes a great little tool that allows your readers to easily share your blog images via Twitter, Facebook, and Pinterest. It is the best option out there for sharing your visual content across the web. Recommended Reading: 25 Growth Hacks Your Content Marketing Desperately Needs 4. Publish Your Content At The  Right  Time When is the best time to publish a blog post? KISSmetrics in corporation with  Dan Zarrella  has been able to crack the code on this very idea. Key Takeaways: Most blog content is read in the mornings. However, men tend to be more likely to read content in the evenings. Monday is the best day of the week to publish content. Most blog posts gets the most traffic around 11am. Saturday and early morning visitors (9am) tend to leave more comments. Monday and Tuesday are the highest drivers of inbound traffic. The take away on this data is  pretty easy to see. It is likely in your best interest to publish your content early in the week, and early in the morning to maximize your social media  impact.

A Horror Show at the Cinemaplex Essays

A Horror Show at the Cinemaplex Essays A Horror Show at the Cinemaplex Essay A Horror Show at the Cinemaplex Essay Assignment: Based on the instance The Movie Exhibition Industry 2013 in the McGraw Hill article, answer the undermentioned inquiries utilizing constructs and models we have discussed in category. Answers should be completed in a short five page write-up utilizing the templets provided below. Short replies / slugs are acceptable ; nevertheless, you must include some degree of item / information sing the tendencies and analysis you are including independent of the slug points. The difficult transcript write-up is due by the start of category on February 25th. We will be holding a treatment based on this assignment in category. It would be helpful if each group member had a transcript of the finished assignment in forepart of him/her. Please supply a screen page that includes the Assignment name, Mgmt 478 , Section figure ( 006, 007, 008, 300 ) and the group members’ names. The cover sheet is the lone page that includes this information. Besides each page must hold a page figure. All pages must hold a basic. Failure to follow any of these arranging issues will incur a class punishment. All words must be spelled right and all sentences must hold right grammar. 1a ) Perform a general environment analysis. What are the relevant tendencies in the environment that are impacting the film industry by the 5 sections listed below? Demographic Socio-cultural Economic Technological Political / Legal 1b ) What are the biggest chances and menaces in the industry? ( Pick no more than 2 of each and lucubrate in 3-4 sentences ) 2 ) Based on an analysis you complete, is the film exhibition industry an attractive and profitable industry in which to take part? ( After finishing the templet, include a short 2-3 sentence appraisal of overall attraction ) . Ensure that you are specific with your analyses of menaces ( e.g. high capital demands is non plenty, for what would capital demands be high? ) Industry Definition: Movie exhibitioners Force Who / What are they? Analysis of Threat ( Use ( + ) to bespeak adds to the menace, ( ) indicates decreases menace – e.g. high capital demands would be a ( – ) for possible new entrants ) Degree of Threat ( High / Medium / Low ) Potential Entrants Substitutes Dickering Power of Suppliers Dickering Power of Buyers Internal Rivalry Overall Profitability of the Incumbents Overall Attractiveness to Entrants ( Barriers to Entry )

DISC Personality Analysis Essay Example | Topics and Well Written Essays - 1000 words

DISC Personality Analysis - Essay Example dard behavioural patterns and on consultation with my colleagues who gave me their opinion on his reaction and nature of response for every situation. The parameters and factors that affect the individual, myself and my boss, have been listed down below and the same is used for further classifying which of the four types is dominating in our personality. On self analysis, my behaviour pattern is generally open and direct. I indicate my preferences directly. I dress fashionably and appear pretty stylish. I love to have a stimulating work environment that would encourage working. I keep material personally and do not go about sharing with colleagues that easily. My place is cluttered and not really spick and span. I am a friendly person with keenness to make new friends. I do jobs swiftly and respond immediately to issues. I enjoy my interactions with people and give it utmost priority. Naturally, since I give respect to my interactions with people, any loss of prestige with my friends is my worst fear. When I am under pressure or tension, I retaliate by being sarcastic or attacking back at the people who are causing it to me. I would like to have my friend, people and colleagues recognise me for my work. I take time to understand the advantages of the work to my friends and clients. I try to understand who makes use of it and how and how do people benefit out of it. This ensures that the work gains security by being flexible and allows me to maintain my status. I am open and welcome suggestions from my colleagues. I respect their ideas and create an atmosphere that is stimulating, enjoyable and playful. This would increase the amount of inputs that a person might get out of the job. I expect my colleagues to be equally stimulating, respecting my opinions and ideas. May be my target is to be admired by my colleagues. But I certainly get irritated by boredom and routine work. If there is a lack of creative job, that really causes excessive boredom. As a matter of

Corn Air Marketing Strategy Essay Example | Topics and Well Written Essays - 1000 words

Corn Air Marketing Strategy - Essay Example There is no doubt that marketing is an effective determinant of a business success in an industry, especially where there is high competition. Customers chose a particular product based on the information available and to which persuades them towards that product. Indeed, the information in the market is provided through the use of marketing. Marketing hence attracts consumers in many ways. Through marketing, the company creates image and branding that distinguishes them from the competitors, and as Shimp (2010) noted, differentiation is essentials especially to an industry where goods are similar. Accordingly, the public is aware of the existence of the commodity and the associated owner. Furthermore, establishing an effective marketing is a sense of pride to the employees while increasing stakeholder satisfaction. As a result, the employees are motivated leading to better service to the customers, particularly to the airline industry. Companies should so spend effectively if they a re to enjoy the benefits of marketing. The emergent of technology has seen many businesses implement various ways of strategy in marketing to promote their products. Most of the advertisements were conducted through TVs, radios, newspapers, journals to provide for public awareness and indeed, it did serve them well since the last decade there was no prevalence of technology as it is today. With the increased information technology, companies have combined the traditional ways and modern ways to spur their economic growth.