Magnetophotocurrent in Organic Bulk Heterojunction Photovoltaic Cells at Low Temperatures and High Magnetic Fields
Magnetophotocurrent in Organic Bulk Heterojunction Photovoltaic Cells at Low Temperatures and High Magnetic Fields
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DOI：
10.1103/physrevapplied.5.044001
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发表时间：
2016-04
影响因子：
4.6
通讯作者：
B. Khachatryan;A. H. Devir-Wolfman;L. Tzabari;N. Tessler;Z. Vardeny;E. Ehrenfreund
中科院分区：
文献类型：
--
作者：
B. Khachatryan;A. H. Devir-Wolfman;L. Tzabari;N. Tessler;Z. Vardeny;E. Ehrenfreund
我们研究了有机体异质结光伏电池中与光生极化子对(PPS)相关的高场(高)磁光电流(MPC)。我们发现，在高场区域()，响应随温度的升高而增加，但随温度的升高而减小。即使在所研究的最高磁场下，响应也根本不饱和。我们将观察到的高场响应归因于PP自旋态内的两种相互竞争的机制：(A)由施主-受主(或正负极化子)因子的差异引起的自旋混合机制(所谓的“机制”)，以及(B)由PP塞曼分裂能级的热布居引起的自旋极化。在高场和高温下的非饱和响应表明，在亚纳秒时间域内存在衰减时间的电荷转移激子(CTE)。随着温度的降低，CTE衰减时间急剧增加，从而促进了热自旋极化对响应的贡献增加。
We study high-field (up to) magnetophotocurrent (MPC) related to photogenerated polaron pairs (PPs) in the temperature rangein organic bulk heterojunction photovoltaic cells. We find that in the high-field regime (),response increases withfor temperaturebut decreases withat.response does not saturate even at the highest field studied, at all. We attribute the observed high-fieldresponse to two competing mechanisms within the PP spin states: (a) a spin-mixing mechanism caused by the difference in the donor-acceptor (or positive-negative polarons)factors (the so-called “mechanism”), and (b) the spin polarization induced by thermal population of the PP Zeeman split levels. The nonsaturatingresponse at high fields and high temperatures indicates that there exist charge-transfer excitons (CTEs) with decay time in the subnanosecond time domain. With decreasing temperature, the CTE decay time sharply increases, thereby promoting an increase of the thermal spin-polarization contribution to theresponse.