Schueppel R, Uhrich C, Pfeiffer M, Leo K, Brier E, Reinold E, Baeuerle P
Institut für Angewandte Photophysik, Technische Universtität Dresden, Germany.
Chemphyschem. 2007 Jul 16;8(10):1497-503. doi: 10.1002/cphc.200700306.
Photoinduced and transient absorption spectroscopy is used to study triplet exciton dynamics in thin films of a new thiophene-based oligomer (DCV3T) and blends of DCV3T and fullerene C60. We find enhanced DCV3T triplet exciton generation in the blend layer, which is explained as an excitonic ping-pong effect: singlet energy transfer from DCV3T to C60, followed by immediate intersystem crossing to C60, and triplet exciton back-transfer. Estimations of the rate constants involved show that the ping-pong effect has an overall efficiency close to unity. The singlet-singlet energy transfer from DCV3T to C60 is demonstrated by efficient quenching of DCV3T luminescence in the blend, leading to sensitized emission of C60. We discuss a promising new concept of solar cells with an enlarged active-layer thickness based on potentially long-ranged triplet exciton diffusion in combination with efficient intersystem crossing.
采用光致和瞬态吸收光谱法研究了一种新型噻吩基低聚物（DCV3T）薄膜以及DCV3T与富勒烯C60混合物中的三重态激子动力学。我们发现在混合层中DCV3T三重态激子的产生有所增强，这被解释为激子乒乓效应：单线态能量从DCV3T转移到C60，随后立即发生系间窜越至C60，然后三重态激子反向转移。对相关速率常数的估计表明，乒乓效应的整体效率接近1。通过混合物中DCV3T发光的有效猝灭证明了从DCV3T到C60的单线态-单线态能量转移，从而导致C60的敏化发射。我们讨论了一种基于潜在的长程三重态激子扩散并结合高效系间窜越的、具有增大活性层厚度的太阳能电池的有前景的新概念。
