Jihong Zheng

Bio: Jihong Zheng is an academic researcher from Henan University. The author has contributed to research in topics: Perovskite (structure) & Passivation. The author has an hindex of 1, co-authored 4 publications receiving 3 citations.

Perovskite Solar Cells Employing a PbSO4(PbO)4 Quantum Dot-Doped Spiro-OMeTAD Hole Transport Layer with an Efficiency over 22.

Abstract: 2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene (spiro-OMeTAD), the most widely used hole transport material in high-efficiency perovskite solar cells (PSCs), still has serious defects, such as moisture absorption and poor long-term conductivity, which seriously restrict further improvement of the power conversion efficiency (PCE) and stability of the cell. Herein, to overcome these problems, inorganic salt PbSO4(PbO)4 quantum dots (QDs) are incorporated into spiro-OMeTAD as the hole transport layer (HTL) for the first time. The incorporated PbSO4(PbO)4 QDs significantly hinder the agglomeration of lithium bis(trifluoromethanesulfonyl)-imide and improve the long-term conductivity through the oxidative interaction between PbSO4(PbO)4 QDs and spiro-OMeTAD and hydrophobicity of the HTL. Furthermore, the spiro-OMeTAD:PbSO4(PbO)4 composite film can effectively passivate perovskite defects at the perovskite/HTL interface, resulting in suppressed interfacial recombination. As a result, the PSC based on the spiro-OMeTAD:PbSO4(PbO)4 HTL shows an improved PCE of 22.66%, which is much higher than that (18.89%) of the control device. PbSO4(PbO)4 also significantly improves the moisture stability for 50 days at room temperature (at RH ∼ 40-50%) without encapsulation. This work indicates that inorganic PbSO4(PbO)4 QDs are crucial materials that can be employed as an additive in spiro-OMeTAD to enhance the efficiency and stability of PSCs.

Effects of the incorporation amount of CdS and Cd(SCN 2 H 4 ) 2 Cl 2 on the performance of perovskite solar cells

Abstract: An excellent organolead halide perovskite film is important for the good performance of perovskite solar cells (PSCs). However, defects in perovskite crystals can affect the photovoltaic properties and stability of solar cells. To solve this problem, this study incorporated a complex of CdS and Cd(SCN 2 H 4 ) 2 Cl 2 into the CH 3 NH 3 PbI 3 active layer. The effects of different doping concentrations of CdS and Cd(SCN 2 H 4 ) 2 Cl 2 on the performance and stability of PSCs were analyzed. Results showed that doping appropriate incorporation concentrations of CdS and Cd(SCN 2 H 4 ) 2 Cl 2 in CH 3 NH 3 PbI 3 can improve the performance of the prepared solar cells. In specific, CdS and Cd(SCN 2 H 4 ) 2 Cl 2 can effectively passivate the defects in perovskite crystals, thereby suppressing the charge recombination in PSCs and promoting the charge extraction at the TiO 2 /perovskite interface. Due to the reduction of perovskite crystal defects and the enhancement of compactness of the CdS:Cd(SCN 2 H 4 ) 2 Cl 2 :CH 3 NH 3 PbI 3 composite film, the stability of PSCs is significantly improved.

Effect of (CH3)2Sn(COOH)2 Electron Transport Layer Thickness on Device Performance in n-i-p Planar Heterojunction Perovskite Solar Cells

Abstract: The electron transport layer (ETL) plays an important role as a buffer layer in the efficient n-i-p planar heterojunction perovskite solar cells (PSCs). Recently, a new ETL, (CH3)2Sn(COOH)2 (CSCO),...

Rationalization of passivation strategies toward high-performance perovskite solar cells.

Abstract: Lead halide perovskite solar cells (PSCs) have shown unprecedented development in efficiency and progressed relentlessly in improving stability. All the achievements have been accompanied by diverse passivation strategies to circumvent the pervasive defects in perovskite materials, which play crucial roles in the process of charge recombination, ion migration, and component degradation. Among the tremendous efforts made to solve these issues and achieve high-performance PSCs, we classify and review both well-established and burgeoning passivation strategies to provide further guidance for the passivation protocols in PSCs, including chemical passivation to eliminate defects by the formation of chemical bonds, physical passivation to eliminate defects by strain relaxation or physical treatments, energetic passivation to improve the stability toward light and oxygen, and field-effect passivation to regulate the interfacial carrier behavior. The subtle but non-trivial consequences from various passivation strategies need advanced characterization techniques combining synchrotron-based X-ray analysis, capacitance-based measurements, spatially resolved imaging, fluorescent molecular probe, Kelvin probe force microscope, etc., to scrutinize the mechanisms. In the end, challenges and prospective research directions on advancing these passivation strategies are proposed. Judicious combinations among chemical, physical, energetic, and field-effect passivation deserve more attention for future high-efficiency and stable perovskite photovoltaics.

Perovskite Solar Cells Employing a PbSO4(PbO)4 Quantum Dot-Doped Spiro-OMeTAD Hole Transport Layer with an Efficiency over 22.

Abstract: 2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene (spiro-OMeTAD), the most widely used hole transport material in high-efficiency perovskite solar cells (PSCs), still has serious defects, such as moisture absorption and poor long-term conductivity, which seriously restrict further improvement of the power conversion efficiency (PCE) and stability of the cell. Herein, to overcome these problems, inorganic salt PbSO4(PbO)4 quantum dots (QDs) are incorporated into spiro-OMeTAD as the hole transport layer (HTL) for the first time. The incorporated PbSO4(PbO)4 QDs significantly hinder the agglomeration of lithium bis(trifluoromethanesulfonyl)-imide and improve the long-term conductivity through the oxidative interaction between PbSO4(PbO)4 QDs and spiro-OMeTAD and hydrophobicity of the HTL. Furthermore, the spiro-OMeTAD:PbSO4(PbO)4 composite film can effectively passivate perovskite defects at the perovskite/HTL interface, resulting in suppressed interfacial recombination. As a result, the PSC based on the spiro-OMeTAD:PbSO4(PbO)4 HTL shows an improved PCE of 22.66%, which is much higher than that (18.89%) of the control device. PbSO4(PbO)4 also significantly improves the moisture stability for 50 days at room temperature (at RH ∼ 40-50%) without encapsulation. This work indicates that inorganic PbSO4(PbO)4 QDs are crucial materials that can be employed as an additive in spiro-OMeTAD to enhance the efficiency and stability of PSCs.

Controlled crystal orientation of two-dimensional Ruddlesden-Popper halide perovskite films for solar cells

Abstract: Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and cost-effective solution-processable fabrication; however, they exhibit poor structural stability. Two-dimensional (2D) Ruddlesden—Popper (RP) perovskites could address the aforementioned issue and present excellent stability because of their hydrophobic organic spacer cations. However, the crystallographic orientation of 2D crystals should be perpendicular to the bottom substrates for charges to transport fast and be collected in solar cells. Moreover, controlling the crystallographic orientation of the 2D RP perovskites prepared by the solution process is difficult. Herein, we reviewed the progress of recent research regarding 2D RP perovskite films with the focus on the crystallographic orientation mechanism and orientation controlling methods. Furthermore, the current issues and prospects of 2D RP perovskites in the photovoltaic field were discussed to elucidate their development and application in the future.