ORCID Profile
0000-0003-2022-002X
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Publisher: Wiley
Date: 02-11-2021
Publisher: MDPI AG
Date: 19-01-2022
DOI: 10.3390/EN15030711
Abstract: Using the optical transfer matrix method, we optimized the layered structure of a conventional and an inverted BHJ OSC with the active layer made of blended PTB7-Th:PNDI-T10 by maximizing the optical absorption and, hence, the JSC. The maximum JSC thus obtained from the optimised structure of the inverted OSC was 139 Am−2 and that of the conventional OSC was 135 Am−2. Simulation of the electric field distribution in both inverted and conventional OSCs showed that the formation of a single CIP was obtained in the active layer of thickness 105 nm in both OSCs. As the light incidents from the ITO side, it was found that excitons were generated more closely to ITO electrode, which favors the efficient charge transport and collection at the opposite electrodes in the inverted OSC, which produces higher JSC.
Publisher: Wiley
Date: 09-04-2019
Publisher: MDPI AG
Date: 27-01-2022
DOI: 10.3390/NANO12030420
Abstract: Thermal stability, closely associated with the operating temperature, is one of the desired properties for practical applications of organic solar cells (OSCs). In this paper, an OSC of the structure of ITO/PEDOT:PSS/P3HT:PCBM/ZnO/Ag was fabricated, and its current-voltage (J-V) characteristics and operating temperature were measured. The operating temperature of the same OSC was simulated using an analytical model, taking into consideration the heat transfer, charge carrier drift-diffusion and different thermal generation processes. The simulated results agreed well with the experimental ones. It was found that the thermalization of charge carriers above the band gap had the highest influence on the operating temperature of the OSCs. The energy off-set at the donor/acceptor interface in the bulk heterojunction (BHJ) was shown to have a negligible impact on the thermal stability of the OSCs. However, the energy off-sets at the electrode/charge-transporting layer and BHJ/charge-transporting layer interfaces had greater impacts on the operating temperature of OSCs at the short circuit current and maximum power point conditions. Our results revealed that a variation over the energy off-set range from 0.1 to 0.9 eV would induce an almost 10-time increase in the corresponding thermal power generation, e.g., from 0.001 to 0.01 W, in the cells operated at the short circuit current condition, contributing to about 16.7% of the total solar power absorbed in the OSC.
Publisher: Hindawi Limited
Date: 19-10-2023
DOI: 10.1155/2023/6696446
Publisher: Wiley
Date: 10-05-2020
Publisher: Wiley
Date: 29-07-2021
Abstract: A comprehensive study of the operating temperature () of three nonfullerene (NF) acceptor‐based bulk heterojunction organic solar cells (BHJ OSCs), two conventional (OSC1 and OSC3) and one inverted (OSC2) structure, is presented. A quantitative analysis of the thermal power generated by photon absorption in transport layers and electrodes, thermalization of photoexcited charge carriers, tail‐state recombination, and resistive heating is conducted. For all three OSCs, the dependence of operating temperature on the voltage is simulated and it is found that OSC1 and OSC2 operate at about 320 K and OSC3 at 319 K. It is also found that the thermal power generated due to thermalization ( P T ) and absorption in other than the active layer () in OSC3 are smaller than those in both OSC1 and OSC2 but the thermal power generated due to the resistive heating ( P R ) is larger in OSC3 than in OSC1 and OSC2, leading to the net power absorbed in the active layer of OSC3 being higher than that in OSC1 and OSC2. Thus, although the operating temperature of all three cells remains in the range from 320 to 321 K, OSC3 shows a better photovoltaic performance.
Publisher: MDPI AG
Date: 15-01-2021
DOI: 10.3390/NANO11010209
Abstract: In this paper, characterisation of exciton generation is carried out in three bulk-heterojunction organic solar cells (BHJ OSCs)—OSC1: an inverted non-fullerene (NF) BHJ OSC OSC2: a conventional NF BHJ OSC and OSC3: a conventional fullerene BHJ OSC. It is found that the overlap of the regions of strong constructive interference of incident and reflected electric fields of electromagnetic waves and those of high photon absorption within the active layer depends on the active layer thickness. An optimal thickness of the active layer can thus be obtained at which this overlap is maximum. We have simulated the rates of total exciton generation and position dependent exciton generation within the active layer as a function of the thicknesses of all the layers in all three OSCs and optimised their structures. Based on our simulated results, the inverted NF BHJ OSC1 is found to have better short circuit current density which may lead to better photovoltaic performance than the other two. It is expected that the results of this paper may provide guidance in fabricating highly efficient and cost effective BHJ OSCs.
No related grants have been discovered for KIRAN SREEDHAR RAM.