Premium
Quantifying interface states and bulk defects in high‐efficiency solution‐processed small‐molecule solar cells by impedance and capacitance characteristics
Author(s) -
Brus Viktor V.,
Kyaw Aung Ko Ko,
Maryanchuk Pavlo D.,
Zhang Jie
Publication year - 2015
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.2586
Subject(s) - capacitance , equivalent series resistance , dielectric , polymer solar cell , electrical impedance , materials science , analytical chemistry (journal) , dielectric spectroscopy , heterojunction , amplitude , optoelectronics , condensed matter physics , energy conversion efficiency , chemistry , electrode , optics , physics , voltage , electrochemistry , quantum mechanics , chromatography
The AC properties of high‐efficiency ( η = 8.01% under standard 100 mW/cm 2 AM1.5 illumination) small‐molecule bulk heterojunction (SM BHJ) solar cells (p‐DTS(FBTTh 2 ) 2 /PC 70 BM) at different DC biases and frequencies of small amplitude (±10 mV) AC signal in the dark at room temperature were investigated in details. We showed the presence of interface states at the heterojunction interface and determined their parameters from the analysis of spectral distributions of real and imaginary components of the measured impedance. The dielectric constant of BHJ ε BHJ = 2.9 was determined from the geometrical capacitance of totally depleted BHJ layer. We explained quantitatively the effect of interface states and series resistance on the measured C‐V characteristics of the SM BHJ solar cells at both low and high frequencies. The quantitative value of the density of defect states in the bulk N = 1.05 × 10 16 cm −3 was determined from the high frequency C‐V characteristic corrected by the effect of the series resistance. Copyright © 2015 John Wiley & Sons, Ltd.