Graphitic carbon nitride doped SnO2 enabling efficient perovskite solar cells with PCEs exceeding 22%

2020 ◽  
Vol 8 (5) ◽  
pp. 2644-2653 ◽  
Author(s):  
Jinbo Chen ◽  
Hua Dong ◽  
Lin Zhang ◽  
Jingrui Li ◽  
Fuhao Jia ◽  
...  

The energy level alignment and carrier mobility of the charge transport layer are of crucial importance for electron extraction and transport in planar heterojunction perovskite solar cells (PSCs).

2020 ◽  
Author(s):  
Yassine Raoui ◽  
Hamid Ez-Zahraouy ◽  
Samrana Kazim ◽  
Shahzada Ahmad

<p>Mixed cation and anion based perovskites solar cells (FAPbI<sub>3</sub>)<sub>0.85</sub>(MAPbBr<sub>3</sub>)<sub>0.15</sub> gave enhanced stability under outdoor conditions, however, it yielded limited power conversion efficiency when SnO<sub>2</sub> and Spiro-OMeTAD were employed as electron and hole transport layer (ETL/HTL). The inevitable interfacial recombination of charge carriers at ETL/perovskite and perovskite/HTL interface diminished the efficiency in planar (n-i-p) perovskite solar cells. Employing computational approach for uni-dimensional device simulator, the effect of band offset on charge recombination at both interfaces were investigated. We noted that it acquired cliff structure when the conduction band minimum of the ETL is lower than that of the perovskite, and thus maximizes interfacial recombination. However, if the conduction band minimum of ETL is higher than perovskite, i.e. spike structure is formed, which improve the performance of solar cell up to an optimum value of conduction band offset allowing to reach performance of 25.21%, with an open circuit voltage (<i>V</i><sub>oc</sub>) of 1231 mV, a current density <i>J</i><sub>sc</sub> of 24.57 mA/cm<sup>2</sup> and a fill factor of 83.28%. Additionally, we found that beyond the optimum offset value, large spike structure could decrease the performance. With an optimized, energy level of Spiro-OMeTAD and the thickness of mixed-perovskite layer performance of 26.56 % can be attained. Our results demonstrate a detailed understanding about the energy level tuning between the charge selective layers and perovskite and furthermore how the improvement in PV performance can be achieved by adjusting the energy level offset.</p>


2018 ◽  
Vol 6 (17) ◽  
pp. 7409-7419 ◽  
Author(s):  
Zhiyong Liu ◽  
Bo Sun ◽  
Xingyue Liu ◽  
Jinghui Han ◽  
Haibo Ye ◽  
...  

Low-temperature printable carbon based planar-heterojunction perovskite solar cells with efficiencies exceeding 15% were demonstrated by using a TiO2/SnO2bilayer as ETL together with CuPc as HTL.


2018 ◽  
Vol 08 (02) ◽  
pp. 1850009
Author(s):  
Enqi Wang ◽  
Peng Chen ◽  
Xingtian Yin ◽  
Bowen Gao ◽  
Wenxiu Que

It is well known that electron transport layer (ETL) plays an indispensable role in the planar heterojunction perovskite solar cells (PSCs). TiO2 is widely used as an ETL material due to its excellent transport properties, however, the presence of defects in the TiO2 layer diminishes the power conversion efficiency (PCE) of the devices. Herein, we introduce a method of low-temperature TiCl4 treatment to deposit a TiOx layer on the surface of TiO2 film, which can effectively passivate trap states at the TiO2 surface. Moreover, the treating process is optimized to be 30[Formula: see text]min using a 40[Formula: see text]mM TiCl4 aqueous solution. Benefiting from this, we obtain the champion device with the highest PCE of 18.47%, which is mainly due to the reduction of surface defects and the deposition of the well-crystallized perovskite films. Besides, the modified PSCs exhibit an average PCE of 17.59%, which is much better than the control devices.


Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 354
Author(s):  
Shaoxi Wang ◽  
He Guan ◽  
Yue Yin ◽  
Chunfu Zhang

With the continuous development of solar cells, the perovskite solar cells (PSCs), whose hole transport layer plays a vital part in collection of photogenerated carriers, have been studied by many researchers. Interface transport layers are important for efficiency and stability enhancement. In this paper, we demonstrated that lithium (Li) and cobalt (Co) codoped in the novel inorganic hole transport layer named NiOx, which were deposited onto ITO substrates via solution methods at room temperature, can greatly enhance performance based on inverted structures of planar heterojunction PSCs. Compared to the pristine NiOx films, doping a certain amount of Li and Co can increase optical transparency, work function, electrical conductivity and hole mobility of NiOx film. Furthermore, experimental results certified that coating CH3NH3PbIxCl3−x perovskite films on Li and Co- NiOx electrode interlayer film can improve chemical stability and absorbing ability of sunlight than the pristine NiOx. Consequently, the power conversion efficiency (PCE) of PSCs has a great improvement from 14.1% to 18.7% when codoped with 10% Li and 5% Co in NiOx. Moreover, the short-circuit current density (Jsc) was increased from 20.09 mA/cm2 to 21.7 mA/cm2 and the fill factor (FF) was enhanced from 0.70 to 0.75 for the PSCs. The experiment results demonstrated that the Li and Co codoped NiOx can be a effective dopant to improve the performance of the PSCs.


2019 ◽  
Vol 3 (3) ◽  
pp. 496-504 ◽  
Author(s):  
Meiyue Liu ◽  
Ziming Chen ◽  
Zhen Chen ◽  
Hin-Lap Yip ◽  
Yong Cao

A cascade-type and energy-level-aligned electron transport layer of ZnO/SnO2/C60-SAM is beneficial for suppressed charge recombination and improved charge extraction in low-bandgap perovskite solar cells, resulting in a reduced Voc loss.


2017 ◽  
Vol 4 (12) ◽  
pp. 170980 ◽  
Author(s):  
Ya-Qiong Wang ◽  
Shou-Bin Xu ◽  
Jian-Guo Deng ◽  
Li-Zhen Gao

The interfacial compatibility between compact TiO 2 and perovskite layers is critical for the performance of planar heterojunction perovskite solar cells (PSCs). A compact TiO 2 film employed as an electron-transport layer (ETL) was modified using 3-aminopropyl trimethoxy silane (APMS) hydrolysate. The power conversion efficiency (PCE) of PSCs composed of an APMS-hydrolysate-modified TiO 2 layer increased from 13.45 to 15.79%, which was associated with a significant enhancement in the fill factor (FF) from 62.23 to 68.04%. The results indicate that APMS hydrolysate can enhance the wettability of γ-butyrolactone (GBL) on the TiO 2 surface, form a perfect CH 3 NH 3 PbI 3 film, and increase the recombination resistance at the interface. This work demonstrates a simple but efficient method to improve the TiO 2 /perovskite interface that can be greatly beneficial for developing high-performance PSCs.


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