Organic Solar Cells Based on PTB7:PC71BM with Cs2CO3 as a Cathode Buffer Layer

Abstract

Bulk heterojunction solar cells were fabricated using poly [[4,8-bis[(2-ethylhexyl) ) buffer layer, and the effect of the buffer layer on the performance of the solar cells was investigated. The Cs 2 CO 3 layer with a thickness of 0.8 nm significantly increased the short circuit current density, open-circuit voltages and fill factors of the solar cells, presumably because of the better contact between the active layer and the cathode and the work function shift of the aluminum cathode. As a result, the power conversion efficiency increased from 1.09 to 2.12%. However, when thickness of the Cs 2 CO 3 exceeded 2 nm, significant degradation was observed. From the results of a stability test, it was suggested that the inserted Cs 2 CO 3 layer had a minimal influence on the lifetime of the unpakcaged devices.

Improvement of bulk heterojunction organic solar cells based on PTB7:PC61BM with small amounts of P3HT

“…23,24) These promising results inspired many recent studies of BHJ solar cells based on PTB7:PC 71 BM, and various techniques have been proposed to further improve the performance of BHJ solar cells. [25][26][27][28][29][30][31][32][33][34][35] Kumar et al reported that the performance of BHJ solar cells based on PTB7:PC 71 BM was improved by utilizing highly conductive PEDOT:PSS films as a hole transport layer (HTL). 36) Ohzeki et al also investigated the effects of drying (solvent annealing) conditions on the performance of BHJ solar cells fabricated using a 1,2-dichlorobenzene (DCB) solution of PTB7:PC 71 BM on a flexible ethylene PET substrate.…”