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Title: Sodium bromide electron-extraction layers for polymer bulk-heterojunction solar cells

Inexpensive and non-toxic sodium bromide (NaBr) was introduced into polymer solar cells (PSCs) as the cathode buffer layer (CBL) and the electron extraction characteristics of the NaBr CBL were investigated in detail. The PSCs based on NaBr CBL with different thicknesses (i.e., 0 nm, 0.5 nm, 1 nm, and 1.5 nm) were prepared and studied. The optimal thickness of NaBr was 1 nm according to the photovoltaic data of PSCs. The open-circuit voltage (V{sub oc}), short-circuit current density (J{sub sc}), fill factor (FF), and power conversion efficiency (PCE) of the PSC with 1 nm NaBr were evaluated to be 0.58 V, 7.36 mA/cm{sup 2}, 0.63, and 2.70%, respectively, which were comparable to those of the reference device with the commonly used LiF. The optimized photovoltaic performance of PSC with 1 nm NaBr was ascribed to the improved electron transport and extraction capability of 1 nm NaBr in PSCs. In addition, the NaBr CBL could prevent the diffusion of oxygen and water vapor into the active layer and prolong the lifetime of the devices to some extent. Therefore, NaBr layer could be considered as a promising non-toxic CBL for PSCs in future.
Authors:
; ; ;  [1] ;  [2] ;  [1] ;  [1] ;  [2]
  1. State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22257072
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; HETEROJUNCTIONS; LITHIUM FLUORIDES; PHOTOVOLTAIC EFFECT; POLYMERS; SODIUM BROMIDES; SOLAR CELLS