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Deping Qian

Bio: Deping Qian is an academic researcher from Linköping University. The author has contributed to research in topics: Polymer solar cell & Organic solar cell. The author has an hindex of 24, co-authored 43 publications receiving 5520 citations. Previous affiliations of Deping Qian include Chinese Academy of Sciences & North China Electric Power University.

Papers
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Journal ArticleDOI
TL;DR: A nonfullerene-based polymer solar cell (PSC) that significantly outperforms fullerene -based PSCs with respect to the power-conversion efficiency and excellent thermal stability is demonstrated for the first time.
Abstract: A nonfullerene-based polymer solar cell (PSC) that significantly outperforms fullerene-based PSCs with respect to the power-conversion efficiency is demonstrated for the first time. An efficiency of >11%, which is among the top values in the PSC field, and excellent thermal stability is obtained using PBDB-T and ITIC as donor and acceptor, respectively.

1,662 citations

Journal ArticleDOI
TL;DR: In this article, fast and efficient charge separation is essential to achieve high power conversion efficiency in organic solar cells (OSCs), and in state-of-the-art OSCs, this is usually achieved by a significant driv
Abstract: Fast and efficient charge separation is essential to achieve high power conversion efficiency in organic solar cells (OSCs). In state-of-the-art OSCs, this is usually achieved by a significant driv ...

1,088 citations

Journal ArticleDOI
TL;DR: In this article, a conjugated polymer based on 5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c′]dithiophene-4,8-dione, named as PBDTBDD, was designed, synthesized and applied in polymer solar cells (PSCs).
Abstract: A new conjugated polymer based on 5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c′]dithiophene-4,8-dione, named as PBDTBDD, was designed, synthesized, and applied in polymer solar cells (PSCs). A power conversion efficiency (PCE) of 6.67% was obtained from the PBDTBDD/PC61BM-based PSC, which is a remarkable result for the PSCs using PC61BM as electron acceptor. The PBDTBDD/PC61BM-based device exhibits a narrow absorption band and excellent quantum efficiency in the range from 500 to 700 nm. Furthermore, PBDTBDD shows a strong aggregation effect in solution state, and the study indicates that although the temperature used in solution preparation has little influence on molecular orientation as well as crystallinity of the D/A blend, it plays an important role in forming proper domain size in the blend. This work provides a good example to reveal the correlation between the morphology of the blend films and the processing temperature of the solution preparation. Furthermore, the study in this work suggests an intere...

622 citations

Journal ArticleDOI
TL;DR: Key optoelectronic properties for donor and acceptor organic semiconductors are identified to obtain organic solar cells with reduced open-circuit voltage losses and high power conversion efficiencies.
Abstract: The open-circuit voltage of organic solar cells is usually lower than the values achieved in inorganic or perovskite photovoltaic devices with comparable bandgaps Energy losses during charge separation at the donor–acceptor interface and non-radiative recombination are among the main causes of such voltage losses Here we combine spectroscopic and quantum-chemistry approaches to identify key rules for minimizing voltage losses: (1) a low energy offset between donor and acceptor molecular states and (2) high photoluminescence yield of the low-gap material in the blend Following these rules, we present a range of existing and new donor–acceptor systems that combine efficient photocurrent generation with electroluminescence yield up to 003%, leading to non-radiative voltage losses as small as 021 V This study provides a rationale to explain and further improve the performance of recently demonstrated high-open-circuit-voltage organic solar cells Key optoelectronic properties for donor and acceptor organic semiconductors are identified to obtain organic solar cells with reduced open-circuit voltage losses and high power conversion efficiencies

613 citations

Journal ArticleDOI
TL;DR: The results suggest OPVs have the potential for further improvement by judicious modulation of ESP and the theoretical studies reveal that the molecular electrostatic potential between PTO2 and IT-4F is large, and the induced intermolecular electric field may assist the charge generation.
Abstract: Although significant improvements have been achieved for organic photovoltaic cells (OPVs), the top-performing devices still show power conversion efficiencies far behind those of commercialized solar cells. One of the main reasons is the large driving force required for separating electron-hole pairs. Here, we demonstrate an efficiency of 14.7% in the single-junction OPV by using a new polymer donor PTO2 and a nonfullerene acceptor IT-4F. The device possesses an efficient charge generation at a low driving force. Ultrafast transient absorption measurements probe the formation of loosely bound charge pairs with extended lifetime that impedes the recombination of charge carriers in the blend. The theoretical studies reveal that the molecular electrostatic potential (ESP) between PTO2 and IT-4F is large, and the induced intermolecular electric field may assist the charge generation. The results suggest OPVs have the potential for further improvement by judicious modulation of ESP.

340 citations


Cited by
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Journal ArticleDOI
17 Apr 2019-Joule
TL;DR: In this paper, a ladder-type electron-deficient core-based central fused ring (Dithienothiophen[3.2-b]- pyrrolobenzothiadiazole) with a benzothiadiadiazoles (BT) core was proposed to fine-tune its absorption and electron affinity.

3,513 citations

Journal ArticleDOI
TL;DR: In this paper, an organic halide salt phenethylammonium iodide (PEAI) was used on HC(NH2)2-CH3NH3 mixed perovskite films for surface defect passivation.
Abstract: In recent years, the power conversion efficiency of perovskite solar cells has increased to reach over 20%. Finding an effective means of defect passivation is thought to be a promising route for bringing further increases in the power conversion efficiency and the open-circuit voltage (VOC) of perovskite solar cells. Here, we report the use of an organic halide salt phenethylammonium iodide (PEAI) on HC(NH2)2–CH3NH3 mixed perovskite films for surface defect passivation. We find that PEAI can form on the perovskite surface and results in higher-efficiency cells by reducing the defects and suppressing non-radiative recombination. As a result, planar perovskite solar cells with a certificated efficiency of 23.32% (quasi-steady state) are obtained. In addition, a VOC as high as 1.18 V is achieved at the absorption threshold of 1.53 eV, which is 94.4% of the Shockley–Queisser limit VOC (1.25 V). Planar perovskite solar cells that have been passivated using the organic halide salt phenethylammonium iodide are shown to have suppressed non-radiative recombination and operate with a certified power conversion efficiency of 23.3%.

3,064 citations

Journal ArticleDOI
TL;DR: The PBDB-T-SF:IT-4F-based OSC device showed a record high efficiency, and an efficiency of over 12% can be obtained with a thickness of 100-200 nm, suggesting the promise of fullerene-free OSCs in practical applications.
Abstract: A new polymer donor (PBDB-T-SF) and a new small molecule acceptor (IT-4F) for fullerene-free organic solar cells (OSCs) were designed and synthesized The influences of fluorination on the absorption spectra, molecular energy levels, and charge mobilities of the donor and acceptor were systematically studied The PBDB-T-SF:IT-4F-based OSC device showed a record high efficiency of 131%, and an efficiency of over 12% can be obtained with a thickness of 100–200 nm, suggesting the promise of fullerene-free OSCs in practical applications

2,292 citations

Journal ArticleDOI
14 Sep 2018-Science
TL;DR: In this article, a semi-empirical model analysis and using the tandem cell strategy to overcome the low charge mobility of organic materials, leading to a limit on the active-layer thickness and efficient light absorption was performed.
Abstract: Although organic photovoltaic (OPV) cells have many advantages, their performance still lags far behind that of other photovoltaic platforms. A fundamental reason for their low performance is the low charge mobility of organic materials, leading to a limit on the active-layer thickness and efficient light absorption. In this work, guided by a semi-empirical model analysis and using the tandem cell strategy to overcome such issues, and taking advantage of the high diversity and easily tunable band structure of organic materials, a record and certified 17.29% power conversion efficiency for a two-terminal monolithic solution-processed tandem OPV is achieved.

2,165 citations