Abstract
To further increase the open-circuit voltage (V oc) of perovskite solar cells (PSCs), many efforts have been devoted to doping the TiO2 electron transport/selective layers by using metal dopants with higher electronegativity than Ti. However, those dopants can introduce undesired charge traps that hinder charge transport through TiO2, so the improvement in the V oc is often accompanied by an undesired photocurrent density–voltage (J–V) hysteresis problem. Herein, it is demonstrated that the use of a rapid flame doping process (40 s) to introduce cobalt dopant into TiO2 not only solves the J–V hysteresis problem but also increases the V oc and power conversion efficiency of both mesoscopic and planar PSCs. The reasons for the simultaneous improvements are two fold. First, the flame-doped Co-TiO2 film forms Co-Ov (cobalt dopant-oxygen vacancy) pairs and hence reduces the number density of Ti3+ trap states. Second, Co doping upshifts the band structure of TiO2, facilitating efficient charge extraction. As a result, for planar PSCs, the flame doping of Co increases the efficiency from 17.1% to 18.0% while reducing the hysteresis from 16.0% to 1.7%. Similarly, for mesoscopic PSCs, the flame doping of Co increases the efficiency from 18.5% to 20.0% while reducing the hysteresis from 7.0% to 0.1%.
| Original language | English |
|---|---|
| Journal | Advanced Energy Materials |
| DOIs | |
| Publication status | Accepted/In press - 2018 Jan 1 |
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All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
Cite this
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Resolving Hysteresis in Perovskite Solar Cells with Rapid Flame-Processed Cobalt-Doped TiO2 . / Kim, Jung Kyu; Chai, Sung Uk; Ji, Yongfei; Levy-Wendt, Ben; Kim, Suk Hyun; Yi, Yeonjin; Heinz, Tony F.; Nørskov, Jens K.; Park, Jong Hyeok; Zheng, Xiaolin.
In: Advanced Energy Materials, 01.01.2018.Research output: Contribution to journal › Article
TY - JOUR
T1 - Resolving Hysteresis in Perovskite Solar Cells with Rapid Flame-Processed Cobalt-Doped TiO2
AU - Kim, Jung Kyu
AU - Chai, Sung Uk
AU - Ji, Yongfei
AU - Levy-Wendt, Ben
AU - Kim, Suk Hyun
AU - Yi, Yeonjin
AU - Heinz, Tony F.
AU - Nørskov, Jens K.
AU - Park, Jong Hyeok
AU - Zheng, Xiaolin
PY - 2018/1/1
Y1 - 2018/1/1
N2 - To further increase the open-circuit voltage (V oc) of perovskite solar cells (PSCs), many efforts have been devoted to doping the TiO2 electron transport/selective layers by using metal dopants with higher electronegativity than Ti. However, those dopants can introduce undesired charge traps that hinder charge transport through TiO2, so the improvement in the V oc is often accompanied by an undesired photocurrent density–voltage (J–V) hysteresis problem. Herein, it is demonstrated that the use of a rapid flame doping process (40 s) to introduce cobalt dopant into TiO2 not only solves the J–V hysteresis problem but also increases the V oc and power conversion efficiency of both mesoscopic and planar PSCs. The reasons for the simultaneous improvements are two fold. First, the flame-doped Co-TiO2 film forms Co-Ov (cobalt dopant-oxygen vacancy) pairs and hence reduces the number density of Ti3+ trap states. Second, Co doping upshifts the band structure of TiO2, facilitating efficient charge extraction. As a result, for planar PSCs, the flame doping of Co increases the efficiency from 17.1% to 18.0% while reducing the hysteresis from 16.0% to 1.7%. Similarly, for mesoscopic PSCs, the flame doping of Co increases the efficiency from 18.5% to 20.0% while reducing the hysteresis from 7.0% to 0.1%.
AB - To further increase the open-circuit voltage (V oc) of perovskite solar cells (PSCs), many efforts have been devoted to doping the TiO2 electron transport/selective layers by using metal dopants with higher electronegativity than Ti. However, those dopants can introduce undesired charge traps that hinder charge transport through TiO2, so the improvement in the V oc is often accompanied by an undesired photocurrent density–voltage (J–V) hysteresis problem. Herein, it is demonstrated that the use of a rapid flame doping process (40 s) to introduce cobalt dopant into TiO2 not only solves the J–V hysteresis problem but also increases the V oc and power conversion efficiency of both mesoscopic and planar PSCs. The reasons for the simultaneous improvements are two fold. First, the flame-doped Co-TiO2 film forms Co-Ov (cobalt dopant-oxygen vacancy) pairs and hence reduces the number density of Ti3+ trap states. Second, Co doping upshifts the band structure of TiO2, facilitating efficient charge extraction. As a result, for planar PSCs, the flame doping of Co increases the efficiency from 17.1% to 18.0% while reducing the hysteresis from 16.0% to 1.7%. Similarly, for mesoscopic PSCs, the flame doping of Co increases the efficiency from 18.5% to 20.0% while reducing the hysteresis from 7.0% to 0.1%.
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U2 - 10.1002/aenm.201801717
DO - 10.1002/aenm.201801717
M3 - Article
JO - Advanced Energy Materials
JF - Advanced Energy Materials
SN - 1614-6832
ER -