Others Exciton Lifetime Paradoxically Enhanced by Dissipation and Decoherence: Toward Efficient Energy Conversion of a Solar Cell

Yamada, Yasuhiro  ,  Yamaji, Youhei  ,  Imada, Masatoshi

115 ( 19 ) 2015-11-06 , American Physical Society , Department of Applied Physics, The University of Tokyo , Quantum-Phase Electronics Center (QPEC), The University of Tokyo
UTokyo Research掲載「"悪い"効果が太陽光発電に役に立つ」 URI: http://www.u-tokyo.ac.jp/ja/utokyo-research/research-news/good-solar-cells-from-bad-effects.html
UTokyo Research "Good solar cells from bad effects" URI: http://www.u-tokyo.ac.jp/en/utokyo-research/research-news/good-solar-cells-from-bad-effects.html
Energy dissipation and decoherence are at first glance harmful to acquiring the long exciton lifetime desired for efficient photovoltaics. In the presence of both optically forbidden (namely, dark) and allowed (bright) excitons, however, they can be instrumental, as suggested in photosynthesis. By simulating the quantum dynamics of exciton relaxations, we show that the optimized decoherence that imposes a quantum-to-classical crossover with the dissipation realizes a dramatically longer lifetime. In an example of a carbon nanotube, the exciton lifetime increases by nearly 2 orders of magnitude when the crossover triggers a stable high population in the dark excitons.


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