TY  - JOUR
A1  - Lai, Huagui
A1  - Luo, Jincheng
A1  - Zwirner, Yannick
A1  - Olthof, Selina
A1  - Wieczorek, Alexander
A1  - Ye, Fangyuan
A1  - Jeangros, Quentin
A1  - Yin, Xinxing
A1  - Akhundova, Fatima
A1  - Ma, Tianshu
A1  - He, Rui
A1  - Kothandaraman, Radha K.
A1  - Chin, Xinyu
A1  - Gilshtein, Evgeniia
A1  - Muller, Andre
A1  - Wang, Changlei
A1  - Thiesbrummel, Jarla
A1  - Siol, Sebastian
A1  - Prieto, Jose Marquez
A1  - Unold, Thomas
A1  - Stolterfoht, Martin
A1  - Chen, Cong
A1  - Tiwari, Ayodhya N.
A1  - Zhao, Dewei
A1  - Fu, Fan
T1  - High-performance flexible all-Perovskite tandem solar cells with reduced V-OC-deficit in wide-bandgap subcell
JF  - Advanced energy materials
N2  - Among various types of perovskite-based tandem solar cells (TSCs), all-perovskite TSCs are of particular attractiveness for building- and vehicle-integrated photovoltaics, or space energy areas as they can be fabricated on flexible and lightweight substrates with a very high power-to-weight ratio. However, the efficiency of flexible all-perovskite tandems is lagging far behind their rigid counterparts primarily due to the challenges in developing efficient wide-bandgap (WBG) perovskite solar cells on the flexible substrates as well as their low open-circuit voltage (V-OC). Here, it is reported that the use of self-assembled monolayers as hole-selective contact effectively suppresses the interfacial recombination and allows the subsequent uniform growth of a 1.77 eV WBG perovskite with superior optoelectronic quality. In addition, a postdeposition treatment with 2-thiopheneethylammonium chloride is employed to further suppress the bulk and interfacial recombination, boosting the V-OC of the WBG top cell to 1.29 V. Based on this, the first proof-of-concept four-terminal all-perovskite flexible TSC with a power conversion efficiency of 22.6% is presented. When integrating into two-terminal flexible tandems, 23.8% flexible all-perovskite TSCs with a superior V-OC of 2.1 V is achieved, which is on par with the V-OC reported on the 28% all-perovskite tandems grown on the rigid substrate.
KW  - all-perovskite tandems
KW  - flexible tandem solar cells
KW  - perovskite
KW  - V OC-deficit
KW  - wide-bandgap
Y1  - 2022
U6  - https://doi.org/10.1002/aenm.202202438
SN  - 1614-6832
SN  - 1614-6840
VL  - 12
IS  - 45
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Caprioglio, Pietro
A1  - Zu, Fengshuo
A1  - Wolff, Christian Michael
A1  - Prieto, Jose A. Marquez
A1  - Stolterfoht, Martin
A1  - Becker, Pascal
A1  - Koch, Norbert
A1  - Unold, Thomas
A1  - Rech, Bernd
A1  - Albrecht, Steve
A1  - Neher, Dieter
T1  - High open circuit voltages in pin-type perovskite solar cells through strontium addition
JF  - Sustainable Energy & Fuels
N2  - The incorporation of even small amounts of strontium (Sr) into lead-base hybrid quadruple cation perovskite solar cells results in a systematic increase of the open circuit voltage (V-oc) in pin-type perovskite solar cells. We demonstrate via absolute and transient photoluminescence (PL) experiments how the incorporation of Sr significantly reduces the non-radiative recombination losses in the neat perovskite layer. We show that Sr segregates at the perovskite surface, where it induces important changes of morphology and energetics. Notably, the Sr-enriched surface exhibits a wider band gap and a more n-type character, accompanied with significantly stronger surface band bending. As a result, we observe a significant increase of the quasi-Fermi level splitting in the neat perovskite by reduced surface recombination and more importantly, a strong reduction of losses attributed to non-radiative recombination at the interface to the C-60 electron-transporting layer. The resulting solar cells exhibited a V-oc of 1.18 V, which could be further improved to nearly 1.23 V through addition of a thin polymer interlayer, reducing the non-radiative voltage loss to only 110 meV. Our work shows that simply adding a small amount of Sr to the precursor solutions induces a beneficial surface modification in the perovskite, without requiring any post treatment, resulting in high efficiency solar cells with power conversion efficiency (PCE) up to 20.3%. Our results demonstrate very high V-oc values and efficiencies in Sr-containing quadruple cation perovskite pin-type solar cells and highlight the imperative importance of addressing and minimizing the recombination losses at the interface between perovskite and charge transporting layer.
Y1  - 2019
U6  - https://doi.org/10.1039/c8se00509e
SN  - 2398-4902
VL  - 3
IS  - 2
SP  - 550
EP  - 563
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -