Fill Factor Analysis of Organic Solar Cell

Fill Factor Analysis of Organic Solar Cell Rashmi Swami, Rajesh Awasthi, Sanjay Tiwari Theoretical Sun powered 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, impede, fill factor and change effectiveness. This paper depends on the investigation of variables that influence the fill factor of natural sun powered cell utilizing MATLAB. Fill factor is determined utilizing customary natural sun based cell model without arrangement and shunt protections and consistent light produced current for two distinct cases â€first utilizing Exponential dull trademark and second utilizing Polynomial dim trademark. We get for exponential V-I relationship increment in ideality factor n, will diminish 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 critical drop in fill factor. Increment or diminishing in an extra factor would in like man ner change fill factor. Dim current can be differed in two different ways, one by changing portability and other by shifting infusion boundary statures. In both the cases fill factor increments proportionately with . Watchwords †Organic sun oriented cell, fill factor, ideality factor, open circuit voltage, HTL, ETL. Presentation Bilayer natural sun powered cell as appeared in fig. 1(a) is a gadget where slight layer of natural material (contributor and acceptor) is utilized between cathodes to change over light into power. This work is totally founded on bilayer structure of natural sun based 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 contributor/HTL and poly(9,9-dioctylfluorene-co-benzothiadiazole) ( F8BT) is natural acceptor/ETL. Fig. 1(b) shows least complex customary natural sunlight based cell model without arrangement and shunt protections. Open circuit voltage, impede, fill factor and effectiveness 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, each of the three components FF, VOC, ISC ought to be huge with the goal that it can convey huge yield power for a similar accidental optical force. (b) Fig. 1 : (a) Bilayer natural sunlight based cell structure. (b) Conventional natural sun powered cell model without arrangement and shunt protections. Reenactment Model and Analysis of Fill Factor Two cases have been considered, one where dull trademark is exponential like p-n intersection and other where dim attributes is polynomial like in space charge constrained gadgets. 1.2.1Exponential Current Voltage Relationship †In this model, dim trademark is accepted to follow exponential current voltage relationship and Iph is thought to be consistent. (1) where n is ideality factor and Vth is warm voltage, Iph is light created current, Id is dull current and I is net yield current. Absolute yield estimated current can be composed as an element of photograph produced current and dim current. (2) Yield intensity of natural sun oriented cell when it is working at voltage V and giving current I- In the event that most extreme force is acquired at voltage Vm, , here accepting (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) In the event that photovoltaic is worked at voltage V and yield current is I, yield force will be- To figure fill factor, one needs to discover the most extreme force which photograph voltaic cell can gracefully. In the event that most extreme force is conveyed at voltage Vm This will give, (9) what's more, (10) At VOC net yield current will be zero. At this condition eq. (8) will give (11) what's more, (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 produced current on the applied voltage implies that fill factor would rely upon it too adjacent 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 †Along these lines shows an extra factor that would influence fill factor. As this factor increments or diminishes, the fill factor ought to in like manner change as well. Results and Conclusions Eq. (3) proposes 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 consistent as it is a component 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 shift keeping the opposite immersion current steady. Subsequently as ideality factor n differs keeping the converse immersion current I0 steady, fill factor of the gadget will stay unaltered. However on the off chance that open circuit voltage (VOC) thought to be consistent by shifting converse immersion current I0 as ideality factor n changes, fill factor will change likewise. Accepting 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 steady, 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 lessen the estimation of fill factor Fig. 2 : Variation of fill factor with ideality steady n. open circuit voltage and light created current are taken to be consistent as 1.25 V and 1 mA-cm-2 separately. 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. Be that as it may, FF will turn out to be just 1 when m is unendingness. 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 dull trademark with consistent light created current we get that expansion in m will build 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 expands and bigger. Recreation results uncovered in fig. 4 show that light created current Iph is a component of applied voltage, implies FF would rely upon it too close to state of dim trademark. A huge reliance of Iph on expanding applied voltage would cause a critical drop in FF. Increment or diminishing in an extra factor would likewise change fill factor. Dim current can be fluctuated in two different ways, one by shifting portability and other by changing infusion boundary statures. In both the cases fill factor increments proportionately with as appeared in fig. 5 and fig. 6. Fig. 4 : Dependence of light produced current on the applied voltage. furthermore, are the gap and electron mobilities individually. 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 gotten 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. 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