Ultrafast Long-Range Charge Separation in Organic Semiconductor Photovoltaic Diodes

被引：797

作者：

Gelinas, Simon ^{[1
]}

Rao, Akshay ^{[1
]}

Kumar, Abhishek ^{[1
]}

Smith, Samuel L. ^{[1
]}

Chin, Alex W. ^{[1
]}

Clark, Jenny ^{[1
]}

van der Poll, Tom S. ^{[2
]}

Bazan, Guillermo C. ^{[2
]}

Friend, Richard H. ^{[1
]}

机构：

[1] Univ Cambridge, Cavendish Lab, Cambridge CB3 0HE, England

[2] Univ Calif Santa Barbara, Ctr Polymers & Organ Solids, Santa Barbara, CA 93106 USA

来源：

SCIENCE | 2014年 / 343卷 / 6170期

基金：

英国工程与自然科学研究理事会; 新加坡国家研究基金会;

关键词：

EXCITON DISSOCIATION; SOLAR-CELLS; PERFORMANCE; ENERGY;

D O I：

10.1126/science.1246249

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Understanding the charge-separation mechanism in organic photovoltaic cells (OPVs) could facilitate optimization of their overall efficiency. Here we report the time dependence of the separation of photogenerated electron hole pairs across the donor-acceptor heterojunction in OPV model systems. By tracking the modulation of the optical absorption due to the electric field generated between the charges, we measure similar to 200 millielectron volts of electrostatic energy arising from electron-hole separation within 40 femtoseconds of excitation, corresponding to a charge separation distance of at least 4 nanometers. At this separation, the residual Coulomb attraction between charges is at or below thermal energies, so that electron and hole separate freely. This early time behavior is consistent with charge separation through access to delocalized pi-electron states in ordered regions of the fullerene acceptor material.

引用

页码：512 / 516

页数：5

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