Spatially resolved investigation of the defect states in methylammonium lead iodide perovskite bicrystals

2019 ◽  
Vol 7 (42) ◽  
pp. 13156-13160 ◽  
Author(s):  
Svetlana Sirotinskaya ◽  
Christian Fettkenhauer ◽  
Daichi Okada ◽  
Yohei Yamamoto ◽  
Doru C. Lupascu ◽  
...  

Introducing a modal system approach for the analytical perovskite thin-film trap physics evaluation. Our study confirms existing models for trap formation in MAPI, substantiating different defect states in the grain boundary and bulk regions.

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 539 ◽  
Author(s):  
Jeoungmin Ji ◽  
Farjana Haque ◽  
Nhu Thi To Hoang ◽  
Mallory Mativenga

We report clear room temperature ambipolar transport in ambient-air processed methylammonium lead iodide (MAPbI3) thin-film transistors (TFTs) with aluminum oxide gate-insulators and indium-zinc-oxide source/drain electrodes. The high ionicity of the MAPbI3 leads to p-type and n-type self-doping, and depending on the applied bias we show that simultaneous or selective transport of electrons and/or holes is possible in a single MAPbI3 TFT. The electron transport (n-type), however, is slightly more pronounced than the hole transport (p-type), and the respective channel resistances range from 5–11 and 44–55 MΩ/μm. Both p-type and n-type TFTs show good on-state characteristics for low driving voltages. It is also shown here that the on-state current of the n-type and p-type TFTs is highest in the slightly PbI2-rich and MAI-rich films, respectively, suggesting controllable n-type or p-type transport by varying precursor ratio.


2021 ◽  
pp. 2102492
Author(s):  
Yeonghun Yun ◽  
Devthade Vidyasagar ◽  
Minho Lee ◽  
Oh Yeong Gong ◽  
Jina Jung ◽  
...  

ACS Photonics ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Md Mehedi Hasan ◽  
Charlotte Clegg ◽  
Max Manning ◽  
Ahmed El Ghanam ◽  
Chen Su ◽  
...  

2019 ◽  
Vol 7 (20) ◽  
pp. 12790-12799 ◽  
Author(s):  
Shalinee Kavadiya ◽  
Joseph Strzalka ◽  
Dariusz M. Niedzwiedzki ◽  
Pratim Biswas

Two orientations in perovskite (CH3NH3PbI3) film, (110) and (002), were resolved and shown to be affected by the thermal annealing procedure.


2020 ◽  
Vol 109 ◽  
pp. 110456 ◽  
Author(s):  
Kindness A. Uyanga ◽  
Sabastine C. Ezike ◽  
Amadi T. Onyedika ◽  
Abdulazeez B. Kareem ◽  
Timothy M. Chiroma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Karl L. Heinze ◽  
Oleksandr Dolynchuk ◽  
Thomas Burwig ◽  
Jaykumar Vaghani ◽  
Roland Scheer ◽  
...  

AbstractVacuum-based co-evaporation promises to bring perovskite solar cells to larger scales, but details of the film formation from the physical vapor phase are still underexplored. In this work, we investigate the growth of methylammonium lead iodide (MAPbI$$_3$$ 3 ) absorbers prepared by co-evaporation of methylammonium iodide (MAI) and lead iodide (PbI$$_2$$ 2 ) using an in situ X-ray diffraction setup. This setup allows us to characterize crystallization and phase evolution of the growing thin film. The total chamber pressure strongly increases during MAI evaporation. We therefore assume the total chamber pressure to be mainly built up by an MAI atmosphere during deposition and use it to control the MAI evaporation. At first, we optimize the MAI to PbI$$_2$$ 2 impingement ratios by varying the MAI pressure at a constant PbI$$_2$$ 2 flux rate. We find a strong dependence of the solar cell device performance on the chamber pressure achieving efficiencies > 14$$\%$$ % in a simple n-i-p structure. On the road to further optimizing the processing conditions we vary the onset time of the PbI$$_2$$ 2 and MAI deposition by delaying the start of the MAI evaporation by t = 0/8/16 min. This way, PbI$$_2$$ 2 nucleates as a seed layer with a thickness of up to approximately 20 nm during this initial stage. Device performance benefits from these PbI$$_2$$ 2 seed layers, which also induce strong preferential thin film orientation as evidenced by grazing incidence wide angle X-ray scattering (GIWAXS) measurements. Our insights into the growth of MAPbI$$_3$$ 3 thin films from the physical vapor phase help to understand the film formation mechanisms and contribute to the further development of MAPbI$$_3$$ 3 and related perovskite absorbers.


2016 ◽  
Vol 3 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Giles E. Eperon ◽  
Clara E. Beck ◽  
Henry J. Snaith

We demonstrate that we can convert hybrid perovskites between methylammonium lead iodide (MAPbI3) and formamidinium lead iodide (FAPbI3) by immersion in solutions of MA or FA iodide at room temperature. The cations diffuse uniformly throughout the bulk films, forming an alloy rather than a bi-layer. Furthermore, this demonstrates good organic cation mobility in these materials.


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