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Energy Level Modification with Carbon Dot Interlayers Enables Efficient Perovskite Solar Cells and Quantum Dot Based Light‐Emitting Diodes
Author(s) -
Zhang Xiaoyu,
Zeng Qingsen,
Xiong Yuan,
Ji Tianjiao,
Wang Chen,
Shen Xinyu,
Lu Min,
Wang Haoran,
Wen Shanpeng,
Zhang Yu,
Yang Xuyong,
Ge Xin,
Zhang Wei,
Litvin Aleksandr P.,
Baranov Alexander V.,
Yao Dong,
Zhang Hao,
Yang Bai,
Rogach Andrey L.,
Zheng Weitao
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201910530
Subject(s) - materials science , quantum dot , perovskite (structure) , light emitting diode , optoelectronics , work function , diode , indium tin oxide , energy conversion efficiency , indium , ethylenediamine , quantum efficiency , solar cell , thin film , nanotechnology , chemical engineering , inorganic chemistry , layer (electronics) , chemistry , engineering
Controlling the transport and minimizing charge carrier trapping at interfaces is crucial for the performance of various optoelectronic devices. Here, how electronic properties of stable, abundant, and easy‐to‐synthesized carbon dots (CDs) are controlled via the surface chemistry through a chosen ratio of their precursors citric acid and ethylenediamine are demonstrated. This allows to adjust the work function of indium tin oxide (ITO) films over the broad range of 1.57 eV, through deposition of thin CD layers. CD modifiers with abundant amine groups reduce the ITO work function from 4.64 to 3.42 eV, while those with abundant carboxyl groups increase it to 4.99 eV. Using CDs to modify interfaces between metal oxide (SnO 2 and ZnO) films and active layers of solar cells and light‐emitting diodes (LEDs) allows to significantly improve their performance. Power conversion efficiency of CH 3 NH 3 PbI 3 perovskite solar cells increases from 17.3% to 19.5%; the external quantum efficiency of CsPbI 3 perovskite quantum dot LEDs increases from 4.8% to 10.3%; and that of CdSe/ZnS quantum dot LEDs increases from 8.1% to 21.9%. As CD films are easily fabricated in air by solution processing, the approach paves the way to a simplified manufacturing of large‐area and low‐cost optoelectronic devices.