Fill Factor Analysis of Organic Solar Cell

Fill Factor Analysis of Organic Solar Cell Rashmi Swami, Rajesh Awasthi, Sanjay Tiwari Conceptual Sun oriented cell is a gadget used to change over light into power. It very well may be made by natural and inorganic materials. Its most significant boundaries are open circuit voltage, cut off, fill factor and transformation effectiveness. This paper depends on the examination of elements that influence the fill factor of natural sun oriented cell utilizing MATLAB. Fill factor is determined utilizing traditional natural sun oriented cell model without arrangement and shunt protections and consistent light produced current for two unique cases â€first utilizing Exponential dim trademark and second utilizing Polynomial dull trademark. We get for exponential V-I relationship increment in ideality factor n, will decrease the fill factor and for polynomial V-I relationship increment in m will expand fill factor. An enormous reliance of light produced current Iph on expanding applied voltage would cause a noteworthy drop in fill factor. Increment or reduction in an extra factor would as needs be change fill factor. Dull current can be changed in two different ways, one by shifting portability and other by fluctuating infusion hindrance statures. In both the cases fill factor increments proportionately with . Catchphrases †Organic sun oriented cell, fill factor, ideality factor, open circuit voltage, HTL, ETL. Presentation Bilayer natural sunlight based cell as appeared in fig. 1(a) is a gadget where slight layer of natural material (giver and acceptor) is utilized between cathodes to change over light into power. This work is totally founded on bilayer structure of natural sun oriented cell as appeared in fig.1(a) in which poly(9,9-dioctylfluorene-co-bis-N,N-(4-butylphenyl)- bis-N,N-phenyl-1,4phenylenediamine) (PFB) is natural giver/HTL and poly(9,9-dioctylfluorene-co-benzothiadiazole) ( F8BT) is natural acceptor/ETL. Fig. 1(b) shows least difficult customary natural sun powered cell model without arrangement and shunt protections. Open circuit voltage, impede, fill factor and proficiency are four significant boundaries of OSC. FF = Vmax Imax/VOC ISC When Vm= VOC and Im= ISC at that point (FF)max=1. For a decent photograph voltaic gadget, every one of the three variables FF, VOC, ISC ought to be huge so it can convey huge yield power for a similar coincidental optical force. (b) Fig. 1 : (a) Bilayer natural sun based cell structure. (b) Conventional natural sun based cell model without arrangement and shunt protections. Reproduction Model and Analysis of Fill Factor Two cases have been examined, one where dim trademark is exponential like p-n intersection and other where dim attributes is polynomial like in space charge restricted gadgets. 1.2.1Exponential Current Voltage Relationship †In this model, dim trademark is expected to follow exponential current voltage relationship and Iph is thought to be steady. (1) where n is ideality factor and Vth is warm voltage, Iph is light produced current, Id is dim current and I is net yield current. All out yield estimated current can be composed as an element of photograph produced current and dim current. (2) Yield intensity of natural sunlight based cell when it is working at voltage V and giving current I- On the off chance that most extreme force is acquired at voltage Vm, , here expecting (3) Here y exp(y) is Lambert’s W work (4) what's more, (5) At VOC net yield current will be zero. At this condition eq. (2) will give (6) 1.2.2 Polynomial Current-Voltage Relationship For this situation it is expected that dim current relies upon the applied voltage in the accompanying way (7) Where K is consistent and . (8) On the off chance that photovoltaic is worked at voltage V and yield current is I, yield force will be- To ascertain fill factor, one needs to discover the most extreme force which photograph voltaic cell can flexibly. In the event that greatest force is conveyed at voltage Vm This will give, (9) also, (10) At VOC net yield current will be zero. At this condition eq. (8) will give (11) also, (12) 1.2.3 Effect of Dark Current on Fill Factor †Simulation utilizing 1D float dispersion electrical displaying of bilayer OSC in MATLAB is finished. We got that the reliance of light created current on the applied voltage implies that fill factor would rely upon it also close to state of dull attributes. A gauge of variety of light current can be acquired by taking proportion of its incentive at short out and open circuit condition †At 0 volt, At VOC, for example The proportion is a proportion of how drop in Iph with the voltage. This proportion can be composed as †In this way shows an extra factor that would influence fill factor. As this factor increments or diminishes, the fill factor ought to as needs be change as well. Results and Conclusions Eq. (3) recommends that as ideality factor n is changed, keeping reverse immersion current I0 and photograph created current Iph consistent, Vm changes in such a way, that (Vm/n) stays steady. So Im will likewise be steady as it is an element of (Vm/n). From eq. (6) open circuit voltage is additionally changes with ideality factor n to such an extent that (VOC/n) stays consistent. It follows from the above thinking that (Im/ISC) and (Vm/VOC) will be unaltered if n will differ keeping the converse immersion current steady. Henceforth as ideality factor n changes keeping the opposite immersion current I0 steady, fill factor of the gadget will stay unaltered. However in the event that open circuit voltage (VOC) thought to be steady by shifting converse immersion current I0 as ideality factor n changes, fill factor will change as needs be. Expecting Iph to be 1 mA-cm-2, I0 to be mA-cm-2 and ideality factor n to be 1, open circuit voltage and round factor come out to be 1.25 volts and 0.9 individually. Taking Iph and VOC consistent, the variety of fill factor with ideality factor n is appeared in fig. 2. We get that expansion in the estimation of ideality factor n, will diminish the estimation of fill factor Fig. 2 : Variation of fill factor with ideality consistent n. open circuit voltage and light produced current are taken to be steady as 1.25 V and 1 mA-cm-2 individually. Eq. (12) shows that fill factor is an element of m. Variety of fill factor with m is appeared in fig. 3. For m = 1, FF = 0.25. As m expands fill factor additionally increments and ways to deal with 1. Notwithstanding, FF will turn out to be just 1 when m is endlessness. For this situation additionally, m is a proportion of the sharpness of the trademark bend. As m expands, I-V bend turns out to be progressively more keen bringing about a high fill factor. For polynomial dim trademark with steady light created current we get that expansion in m will expand fill factor which ways to deal with 1 Fig. 3 : Variation of fill factor with m. fill factor ways to deal with 1 as m increases and bigger. Reproduction results uncovered in fig. 4 show that light created current Iph is an element of applied voltage, implies FF would rely upon it also next to state of dull trademark. An enormous reliance of Iph on expanding applied voltage would cause a critical drop in FF. Increment or diminishing in an extra factor would as needs be change fill factor. Dim current can be shifted in two different ways, one by fluctuating portability and other by changing infusion obstruction statures. In both the cases fill factor increments proportionately with as appeared in fig. 5 and fig. 6. Fig. 4 : Dependence of light created current on the applied voltage. what's more, are the gap and electron mobilities separately. what's more, are the infusion hindrances at anode and cathode separately. Fig. 5 : Variation of fill factor with for 0.1eV and 0.3eV infusion hindrance statures. Various focuses have been acquired by evolving portability. Fig. 6 : Variation of fill factor with for transporter mobilities and . Various focuses have been acquired by changing infusion boundary stature. References J. A. Barker, C. M. Ramsdale, and N. C. Greenham, â€Å"Modeling the current-voltage attributes of bilayer polymer photovoltaic devices†, Physical Review B 67, (2003), 075205. D. P. Grubera, G. Meinhardtb and W. Papousekc, Modeling the light ingestion in natural photovoltaic gadgets, Solar Energy Materials and Solar Cells, 87, (2005), 215-223. J. Wagner, T. Fritz, and H. Bottcher, Computer demonstrating of natural slight film sun powered cells exciton model of photocurrent age, Physica Status Solidi A, 136, (1993), 423. Y. Roichman and N. Tessler, â€Å" Generalized Einstein connection for cluttered semiconductors suggestions for gadget performance†, Appl. Phys. Lett., 80, (2002), 1948. J. C. Scott and G. G. Malliaras, â€Å"Charge infusion and recombination at the metal-natural 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 % effective natural plastic sunlight based cells†, Appl. Phys. Lett., 78, (2001), 841-843 B. K. Hag, P. S. Davids, I. H. Cambell and D. L. Smith, â€Å"Device model examination of bilayer natural light emanating doide†, J. Appl. Phys., 84, (2000), 1974. P. W. M. Blom, M. J. M. de Jong and S. Breedijk, â€Å"Temperature subordinate electron opening recombination in polymer light emanating diodes†, Appl. Phys. Lett., 71, (1997), 930. C. M. Ramsdale, J. A. Barker, A. C. Arias, J. D. MacKenzie, R. H. Companion and N. C. Greenham, â€Å"The beginning of open circuit voltage in polyfluorene-based photovoltaic device†, J. Appl. Phys, 92, (2002),4266. B. Mazhari, â€Å"An improved sunlight based cell circuit model for natural sun powered cells†, Solar Energy Materials Solar Cells, 90, (2002), 1021.