Charge-Transporting-Layer-Free, Vacuum-Free, All-Inorganic CsPbIBr2 Perovskite Solar Cells Via Dipoles-Adjusted Interface.

Wentao Zhang,Dazheng Chen,Weidong Zhu,Chunfu Zhang,Qubo Jiang,Ziming Wei,Yuting Zhang,Hailong You,Zeyulin Zhang,Fengqin He

doi:10.3390/nano10071324

Wentao Zhang, Dazheng Chen + Show 8 more

Open Access

https://doi.org/10.3390/nano10071324

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Abstract

The inorganic perovskite has a better stability than the hybrid halide perovskite, and at the same time it has the potential to achieve an excellent photoelectric performance as the organic-inorganic hybrid halide perovskite. Thus, the pursuit of a low-cost and high-performance inorganic perovskite solar cell (PSC) is becoming the research hot point in the research field of perovskite devices. In setting out to build vacuum-free and carbon-based all-inorganic PSCs with the traits of simple fabrication and low cost, we propose the ones with a simplified vertical structure of FTO/CsPbIBr2/carbon upon interfacial modification with PEI species. In this structure, both the electron-transporting-layer and hole-transporting-layer are abandoned, and the noble metal is also replaced by the carbon paste. At the same time, FTO is modified by PEI, which brings dipoles to decrease the work function of FTO. Through our measurements, the carrier recombination has been partially suppressed, and the performance of champion PSCs has far exceeded the control devices without PEI modification, which yields a power conversion efficiency of 4.9% with an open circuit voltage of 0.9 V and a fill factor of 50.4%. Our work contributes significantly to give an available method to explore charge-transporting-layer-free, low-cost, and high-performance PSCs.

Highlights

The superior properties of the adjustable band gap, the great light absorption, and the high carrier mobilities promote the perovskite materials to a new star against the backdrop of rapid advancement of science and technology in the photovoltaic society [1,2,3,4]
We developed a low-cost and simple process to make all-inorganic, charge-transporting-layer, vacuum-free and carbon-based perovskite solar cell (PSC) with the structure of fluorine-doped tin oxide (FTO)/CsPbIBr2/carbon by the modification of polyethyleneimine (PEI) upon the FTO substrate
Since the conduction band minimum (CBM) of FTO is lower than that of CsPbIBr2, while the valence band maximum (VBM) of CsPbIBr2 is smaller than the Fermi level of carbon electrode

Summary

Introduction

The superior properties of the adjustable band gap, the great light absorption, and the high carrier mobilities promote the perovskite materials to a new star against the backdrop of rapid advancement of science and technology in the photovoltaic society [1,2,3,4]. In addition to the hole/electron transporting layers, the vacuum metal deposition method is usually adopted to deposit the noble metal such as silver and gold to make the electrodes in the fabrication of PSCs [20]. Carbon material has the combined superiorities of low cost, excellent chemical stability, and easy preparation In this regard, many researchers are focused on carbon-based all-inorganic PSC to develop an excellent stability and simple process device with HTL-free or abandon noble metal electrodes [21,22,23]. We developed a low-cost and simple process to make all-inorganic, charge-transporting-layer, vacuum-free and carbon-based PSC with the structure of FTO/CsPbIBr2/carbon by the modification of polyethyleneimine (PEI) upon the FTO substrate. The champion device yields a PCE of 4.9% with a Voc of 0.9 V and FF of 50.4%, which has greatly exceeded the control devices without the PEI modification

Materials Information

Device Fabrication

Device Characterization

Results and Discussion

Conclusions