Optimization of photocurrent in bulk heterojunction organic solar cells using optical admittance analysis method

An Alternative Approach to Simulate the Power Conversion Efficiency of Bulk Heterojunction Organic Solar Cells

“…The exciton generation rate in the active layer can be calculated using OAAM [ 19,20 ] or OTMM [ 11,17,18 ] described in the following section. However, for comparison of results, here, we have applied both the methods for the simulations.…”

“…The optical admittance of the substrate is calculated as [ 19,20 ] where is the complex refractive index of the substrate and [Siemens] is the admittance of air. Using Equation () and (), then, the total reflectance from the solar cell is calculated as [ 19,20 ] …”

Characterising Exciton Generation in Bulk-Heterojunction Organic Solar Cells

“…Simulations of the position dependent exciton generation rate within the active layer j of the following three BHJ OSC1, OSC2, and OSC3 have been carried out. The schematic structures of OSC1, OSC2, and OSC3 are shown in Figure 2 a–c, respectively, and the details of their structures are as follows: OSC1: an inverted BHJ OSC with a non-fullerene acceptor of the structure: Glass/indium tin oxide (ITO) (150 nm)/zinc oxide (ZnO) (30 nm)/Poly[(2,6-(4,8-bis(5-(2-ethylhexylthio)-4-fluorothiophen-2-yl)-benzo [1,2-b:4,5-b′]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1’,2′-c:4′,5′-c’]dithiophene-4,8-dione)]: C 94 H 78 F 4 N 4 O 2 S 4 (PBDBTSF:IT4F)/molybdenum trioxide (MoO 3 )(10 nm)/Aluminium (Al) (100 nm) [ 47 , 48 ] ( Figure 2 a); OSC2: a conventional non-fullerene BHJ OSC of the structure: Glass/ITO(150 nm)/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) (30 nm)/PBDB-T-SF:IT-4F/Poly(9,9-bis(3′-( N , N -dimethyl)- N -ethylammoinium-propyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene))dibromide (PFN-Br) (5 nm)/Al (100 nm) [ 49 ] ( Figure 2 b); and OSC3: a conventional fullerene BHJ OSC of the structure: Glass/ITO (180 nm)/PEDOT:PSS (45 nm)/poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM)/Lithium Fluoride (LiF) (1 nm)/Al (100 nm) [ 50 , 51 ] ( Figure 2 c). It may be noted that the chosen thicknesses of the layers, other than the active layer, in the above three OSCs are the optimal thicknesses obtained from experiments cited above.…”

“…Before presenting the details of our simulation, it is desirable to check the accuracy of our simulation by comparing the simulated with some experimental results. For this purpose, we calculated of OSC1, OSC2, and OSC3 using Equations (1)–(10), which require the input parameters given in Table 1 and experimental values of the refractive index and extinction coefficient (where l = 1, 2, j , 4, and 5) for PBDBTSF:IT4F and PFN-Br from [ 49 , 52 ], for the Glass, ITO, P3HT:PCBM, PEDOT:PSS, LiF and Al from [ 50 , 51 , 53 , 54 , 55 ], and for ZnO and MoO 3 from [ 56 ]. For completeness, the experimental values of n j and k j of the two active layer materials PBDBTSF:IT4F and P3HT:PCBM are plotted in Figure 3 as a function of the wavelength of the incident light.…”

“…The simulated for OSC1, OSC2, and OSC3, thus obtained, are plotted as a function of the active layer thickness in Figure 4 along with the experimental results from [ 47 ] for OSC1, from [ 49 ] for OSC2, and from [ 50 , 51 ] for OSC3. According to Figure 4 , the simulated results of agree reasonably well with the experimental ones and hence prove that our simulation can be regarded to be reasonably accurate.…”