TY  - JOUR
A1  - Pisoni, Stefano
A1  - Stolterfoht, Martin
A1  - Lockinger, Johannes
A1  - Moser, Thierry
A1  - Jiang, Yan
A1  - Caprioglio, Pietro
A1  - Neher, Dieter
A1  - Buecheler, Stephan
A1  - Tiwari, Ayodhya N.
T1  - On the origin of open-circuit voltage losses in flexible n-i-p perovskite solar cells
JF  - Science and technology of advanced materials : STAM
N2  - The possibility to manufacture perovskite solar cells (PSCs) at low temperatures paves the way to flexible and lightweight photovoltaic (PV) devices manufactured via high-throughput roll-to-roll processes. In order to achieve higher power conversion efficiencies, it is necessary to approach the radiative limit via suppression of non-radiative recombination losses. Herein, we performed a systematic voltage loss analysis for a typical low-temperature processed, flexible PSC in n-i-p configuration using vacuum deposited C-60 as electron transport layer (ETL) and two-step hybrid vacuum-solution deposition for CH3NH3PbI3 perovskite absorber. We identified the ETL/absorber interface as a bottleneck in relation to non-radiative recombination losses, the quasi-Fermi level splitting (QFLS) decreases from similar to 1.23 eV for the bare absorber, just similar to 90 meV below the radiative limit, to similar to 1.10 eV when C-60 is used as ETL. To effectively mitigate these voltage losses, we investigated different interfacial modifications via vacuum deposited interlayers (BCP, B4PyMPM, 3TPYMB, and LiF). An improvement in QFLS of similar to 30-40 meV is observed after interlayer deposition and confirmed by comparable improvements in the open-circuit voltage after implementation of these interfacial modifications in flexible PSCs. Further investigations on absorber/hole transport layer (HTL) interface point out the detrimental role of dopants in Spiro-OMeTAD film (widely employed HTL in the community) as recombination centers upon oxidation and light exposure. [GRAPHICS] .
KW  - Perovskite solar cell
KW  - flexible
KW  - interface engineering
KW  - non-radiative recombination
KW  - quasi-Fermi level splitting
Y1  - 2019
U6  - https://doi.org/10.1080/14686996.2019.1633952
SN  - 1468-6996
SN  - 1878-5514
VL  - 20
SP  - 786
EP  - 795
PB  - Taylor & Francis
CY  - Abingdon
ER  -