Toward Revealing the Critical Role of Perovskite Coverage in Highly Efficient Electron-Transport Layer-Free Perovskite Solar Cells: An Energy Band and Equivalent Circuit Model Perspective

Advanced Energy Materials

2019

Self Cite

Perovskite solar cells (PSCs) have shown great potential for photovoltaic applications with their unprecedented power conversion efficiency advancement. Such devices generally have a complex structure design with high temperature processed TiO2 as the electron transport layer (ETL). Further careful design of device configuration to fully tap the potentials of perovskite materials is expected. Particularly, for the practical application of PSCs, it is crucial to simplify their device structures thus the associated manufacturing process and cost while maintaining their efficiency to be comparable with the conventional devices. But how simple is simple? ETL‐free PSCs promise the simplest structured, thus simple manufacturing processes and low cost large area PSCs in practical applications. They can also help the further exploration of the great potential of perovskite materials and understanding the working principle of PSCs. Within this review, the evolution of the PSC is outlined by discussing the recent advances in the simplification of device configuration and processes for cost effective, highly efficient, and robust PSCs, with a focus on ETL‐free PSCs. Their advancement, key issues, working mechanism, existing problems, and future performance enhancements. This review aims to promote the future development of low cost and robust ETL‐free PSCs toward more efficient power output.

Section: Wwwadvancedsciencenewscomsupporting

confidence: 77%

Section: Coverage Of Perovskite Filmmentioning

confidence: 99%

“…[86] The I-V respond of the TiO 2 /spiro-MeOTAD heterojunction based device (Figure 14a) suggests that such a heterojunction has well rectifying characteristics which can avoid the device from being short circuited. [41,86] Further experiment suggests that when coverage decreases, the device performance drops significantly. Huang et al demonstrated systematically the crucial role of high perovskite coverage in high-efficiency ETL-free PSCs from an energy band and equivalent circuit point of view.…”

Section: Coverage Of Perovskite Filmmentioning

confidence: 99%

Section: Carrier Life Time Of Perovskite Filmmentioning

confidence: 99%

Section: Carrier Life Time Of Perovskite Filmmentioning

confidence: 99%

See 3 more Smart Citations

Simple, Robust, and Going More Efficient: Recent Advance on Electron Transport Layer‐Free Perovskite Solar Cells

Advanced Energy Materials

2019

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Towards Simplifying the Device Structure of High‐Performance Perovskite Solar Cells

Liu²,

Liang³

et al. 2020

Adv Funct Materials

Perovskite solar cells (PSCs) are considered one of the most promising nextgeneration examples of high-tech photovoltaic energy converters, as they possess an unprecedented power conversion efficiency with low cost. A typical high-performance PSC generally contains a perovskite active layer sandwiched between an electron-transport layer (ETL) and a hole-transport layer (HTL). The ETL and HTL contribute to the charge extraction in the PSC. However, these additional two layers complicate the manufacturing process and raise the cost. To extend this technology for commercialization, it is highly desired that the structure of PSCs is further simplified without sacrificing their photovoltaic performances. Thus, ETL-free or/and HTL-free PSCs are developed and attract more and more interest. Herein, the commonly used methods in reducing the defect density and optimizing the energy levels in conventional PSCs in order to simplify their structures are summarized. Then, the development of diverse ETL-free or/and HTL-free PSCs is discussed, with the PSCs classified, including their working principles, implemented technologies, remaining challenges, and future perspectives. The aim is to redirect the way toward low-cost and high-performance PSCs with the simplest possible architecture.

Synergistic Interface Energy Band Alignment Optimization and Defect Passivation toward Efficient and Simple‐Structured Perovskite Solar Cell

Zhang

et al. 2020

Advanced Science

Self Cite

Efficient electron transport layer–free perovskite solar cells (ETL‐free PSCs) with cost‐effective and simplified design can greatly promote the large area flexible application of PSCs. However, the absence of ETL usually leads to the mismatched indium tin oxide (ITO)/perovskite interface energy levels, which limits charge transfer and collection, and results in severe energy loss and poor device performance. To address this, a polar nonconjugated small‐molecule modifier is introduced to lower the work function of ITO and optimize interface energy level alignment by virtue of an inherent dipole, as verified by photoemission spectroscopy and Kelvin probe force microscopy measurements. The resultant barrier‐free ITO/perovskite contact favors efficient charge transfer and suppresses nonradiative recombination, endowing the device with enhanced open circuit voltage, short circuit current density, and fill factor, simultaneously. Accordingly, power conversion efficiency increases greatly from 12.81% to a record breaking 20.55%, comparable to state‐of‐the‐art PSCs with a sophisticated ETL. Also, the stability is enhanced with decreased hysteresis effect due to interface defect passivation and inhibited interface charge accumulation. This work facilitates the further development of highly efficient, flexible, and recyclable ETL‐free PSCs with simplified design and low cost by interface electronic structure engineering through facile electrode modification.