TY  - JOUR
A1  - Le Corre, Vincent M.
A1  - Stolterfoht, Martin
A1  - Perdigon Toro, Lorena
A1  - Feuerstein, Markus
A1  - Wolff, Christian Michael
A1  - Gil-Escrig, Lidon
A1  - Bolink, Henk J.
A1  - Neher, Dieter
A1  - Koster, L. Jan Anton
T1  - Charge Transport Layers Limiting the Efficiency of Perovskite Solar Cells: How To Optimize Conductivity, Doping, and Thickness
JF  - ACS Applied Energy Materials
N2  - Perovskite solar cells (PSCs) are one of the main research topics of the photovoltaic community; with efficiencies now reaching up to 24%, PSCs are on the way to catching up with classical inorganic solar cells. However, PSCs have not yet reached their full potential. In fact, their efficiency is still limited by nonradiative recombination, mainly via trap-states and by losses due to the poor transport properties of the commonly used transport layers (TLs). Indeed, state-of-the-art TLs (especially if organic) suffer from rather low mobilities, typically within 10(-5) and 10(-2) cm(-2) V-1 s(-1), when compared to the high mobilities, 1-10 cm(-2) V-1 s(-1), measured for perovskites. This work presents a comprehensive analysis of the effect of the mobility, thickness, and doping density of the transport layers based on combined experimental and modeling results of two sets of devices made of a solution-processed high-performing triple-cation (PCE approximate to 20%). The results are also cross-checked on vacuum-processed MAPbI(3) devices. From this analysis, general guidelines on how to optimize a TL are introduced and especially a new and simple formula to easily calculate the amount of doping necessary to counterbalance the low mobility of the TLs.
KW  - perovskite solar cells
KW  - transport layers
KW  - conductivity
KW  - doping
KW  - charge transport
Y1  - 2019
U6  - https://doi.org/10.1021/acsaem.9b00856
SN  - 2574-0962
VL  - 2
IS  - 9
SP  - 6280
EP  - 6287
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Ghani, Fatemeh
A1  - Opitz, Andreas
A1  - Pingel, Patrick
A1  - Heimel, Georg
A1  - Salzmann, Ingo
A1  - Frisch, Johannes
A1  - Neher, Dieter
A1  - Tsami, Argiri
A1  - Scherf, Ullrich
A1  - Koch, Norbert
T1  - Charge Transfer in and Conductivity of Molecularly Doped Thiophene-Based Copolymers
JF  - Journal of polymer science : B, Polymer physics
N2  - The electrical conductivity of organic semiconductors can be enhanced by orders of magnitude via doping with strong molecular electron acceptors or donors. Ground-state integer charge transfer and charge-transfer complex formation between organic semiconductors and molecular dopants have been suggested as the microscopic mechanisms causing these profound changes in electrical materials properties. Here, we study charge-transfer interactions between the common molecular p-dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane and a systematic series of thiophene-based copolymers by a combination of spectroscopic techniques and electrical measurements. Subtle variations in chemical structure are seen to significantly impact the nature of the charge-transfer species and the efficiency of the doping process, underlining the need for a more detailed understanding of the microscopic doping mechanism in organic semiconductors to reliably guide targeted chemical design.
KW  - charge transfer
KW  - conducting polymers
KW  - doping
KW  - thiophene
Y1  - 2015
U6  - https://doi.org/10.1002/polb.23631
SN  - 0887-6266
SN  - 1099-0488
VL  - 53
IS  - 1
SP  - 58
EP  - 63
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -