Comparing the Calculated Fermi Level Splitting with the Open-Circuit Voltage in Various Perovskite Cells

Journal article (2019)

Authors

Dengyang Guo ChemE/Opto-electronic Materials - AS
V.M. Caselli ChemE/Opto-electronic Materials - AS
E.M. Hutter ChemE/Opto-electronic Materials - AS
T.J. Savenije ChemE/Opto-electronic Materials - AS
Research Group
ChemE/Opto-electronic Materials (AS) (TU Delft)
Copyright: © 2019 Dengyang Guo, V.M. Caselli, E.M. Hutter, T.J. Savenije
DOI: https://doi.org/10.1021/acsenergylett.9b00431
More Info
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Published Date

2019

Language

English

Faculty

Applied Sciences

Department

ChemE/Chemical Engineering

Research Group

ChemE/Opto-electronic Materials

Abstract


While the power conversion efficiency of metal halide perovskite (MHP) solar cells has increased enormously, the open-circuit voltage, V
oc
, is still below the conceivable limit. Here, we derive the Fermi level splitting, μ
F
, for various types of noncontacted MHPs, which sets a limit for their achievable V
oc
, using rate constants and mobilities obtained from time-resolved photoconductivity measurements. Interestingly, we find that for vacuum-evaporated MAPbI
3
and K
+
-doped (MA,FA,Cs)Pb(I/Br)
3
, the μ
F
/e values are close to the reported V
oc
values. This implies that for an improvement of the V
oc
, charge carrier recombination within the bare perovskite has to be reduced. On the other hand, for MHPs with Cs
+
and/or Rb
+
addition, the experimental V
oc
is still below μ
F
/e, suggesting that higher voltages are feasible by optimizing the transport layers. The presented approach will help to select which techniques and transport layers are beneficial to improve the efficiency of MHP solar cells.