Observation of Triplet Exciton Formation in a Platinum-Sensitized Organic Photovoltaic Device.
Observation of Triplet Exciton Formation in a Platinum-Sensitized Organic Photovoltaic Device.
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铂敏化有机光伏器件中三线态激子形成的观察。
DOI：
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发表时间：
2011
影响因子：
5.7
通讯作者：
S. Bradforth
中科院分区：
文献类型：
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作者：
S. Roberts;Cody W. Schlenker;V. Barlier;R. McAnally;Yuyuan Zhang;Joseph N Mastron;M. Thompson;S. Bradforth
有机光催化剂（OPV）由于其低生产成本而成为一种有前途的新技术。然而，OPV效率仍然很低，因为激子在其寿命期间通常仅扩散105 -20 nm，限制了光吸收层的有效厚度。改善OPV的一种策略是通过将激子转化为三重态来增加激子寿命，三重态通常比单重态激子持续长10（3）-10（5）倍。我们提出了飞秒瞬态吸收和稳态光伏测量的模型OPV系统由二苯基并四苯（DPT）薄膜掺杂铂四苯基苯并卟啉（Pt（TPBP））。Pt（TPBP）的光激发产生单重激发，其在转移到DPT主体基质之前快速地在系统间交叉到三重态。这种转移是快速和有效的，发生在35 ps与85%的转化率的卟啉单线态DPT三重态。这些三重态激子导致增强的光电流响应，其随器件厚度而增加。
Organic photovoltaics (OPVs) constitute a promising new technology due to their low production costs. However, OPV efficiencies remain low because excitons typically diffuse only ∼5-20 nm during their lifetime, limiting the effective thickness of the light-absorbing layer. One strategy to improve OPVs is to increase exciton lifetimes by converting them into triplet states, which typically persist 10(3)-10(5) times longer than singlet excitons. We present femtosecond transient absorption and steady-state photovoltaic measurements of a model OPV system consisting of diphenyltetracene (DPT) films doped with platinum tetraphenylbenzoporphyrin (Pt(TPBP)). Photoexcitation of Pt(TPBP) creates a singlet excitation that rapidly intersystem crosses to a triplet state before transferring to the DPT host matrix. This transfer is rapid and efficient, occurring in 35 ps with an 85% conversion ratio of porphyrin singlets to DPT triplets. These triplet excitons lead to enhanced photocurrent response that increases with device thickness.