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Unraveling Charge Separation and Transport Mechanisms in Aqueous‐Processed Polymer/CdTe Nanocrystal Hybrid Solar Cells
Author(s) -
Wang Lei,
Wang HaiYu,
Wei HaoTong,
Zhang Hao,
Chen QiDai,
Xu HuaiLiang,
Han Wei,
Yang Bai,
Sun HongBo
Publication year - 2014
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201301882
Subject(s) - materials science , nanocrystal , aqueous solution , hybrid solar cell , cadmium telluride photovoltaics , photocurrent , charge carrier , polymer , quantum dot , nanotechnology , energy conversion efficiency , quantum dot solar cell , nanoparticle , effective nuclear charge , surface charge , chemical physics , chemical engineering , polymer solar cell , optoelectronics , ion , chemistry , organic chemistry , engineering , composite material
Recently great progress has been achieved in highly effective hybrid solar cells fabricated using aqueous materials. The state‐of‐the‐art energy conversion efficiency has been close to 5% with high photocurrent. However, charge separation and transport mechanism in the aqueous‐processed hybrid solar cells are rarely reported and are usually assumed to be similar to oil‐phase processed systems; that is, self‐assembly polymers are mainly responsible for charge separation and carrier transport. To date, this assumption has prohibited further improvement of the conversion efficiency in aqueous‐processed hybrid systems by adopting any appropriate technique routes. Here, ultrafast carrier dynamics in these hybrid solar cells consisting of poly( p ‐phenylenevinylene) (PPV)‐based aqueous polymers and water‐solution CdTe nanocrystals (NCs) are investigated in detail. Self‐charge separation in grown CdTe NC partly capped CdS shell layers after anneal treatment is unambiguously identified. Different from their oil‐soluble counterparts, these core/shell nanocrystals do not have the restrictions of quantum confinement and surface ligands, form effective charge transport networks, and play a dominant role in the charge separation and carrier transport processes. These findings provide a greater understanding on the fundamental photophysics in aqueous‐processed hybrid systems.