Over 24% Efficient Poly(vinylidene fluoride) (PVDF)‐Coordinated Perovskite Solar Cells with a Photovoltage up to 1.22 V

Abstract

Recently, organic–inorganic metal halide perovskite solar cells (PSCs) have achieved rapid improvement, however, the efficiencies are still behind the Shockley–Queisser theory mainly due to their high energy loss (ELOSS) in open‐circuit voltage (VOC). Due to the polycrystalline nature of the solution‐prepared perovskite films, defects at the grain boundaries as the non‐radiative recombination centers greatly affect the VOC and limit the device efficiency. Herein, poly(vinylidene fluoride) (PVDF) is introduced as polymer‐templates in the perovskite film, where the fluorine atoms in the PVDF network can form strong hydrogen‐bonds with organic cations and coordinate bonds with Pb2+. The strong interaction between PVDF and perovksite enables slow crystal growth and efficient defect passivation, which effectively reduce non‐radiation recombination and minimize ELOSS of VOC. PVDF‐based PSCs achieve a champion efficiency of 24.21% with a excellent voltage of 1.22 V, which is one of the highest VOC values reported for FAMAPb(I/Br)3‐based PSCs. Furthermore, the strong hydrophobic fluorine atoms in PVDF endow the device with excellent humidity stability, the unencapsulated solar cell maintain the initial efficiency of >90% for 2500 h under air ambient of ≈50% humid and a consistently high VOC of 1.20 V.

Fluorinated Graphene–Lewis-Base Polymer Composites as a Multifunctional Passivation Layer for High-Performance Perovskite Solar Cells

“…This is consistent with the trend of V oc . 48 These results indicate that the synergistic action of the two additives reduces defects and improves the charge transfer kinetics. According to the equation In order to further study the charge recombination mechanism in PSCs, the variation of V oc with light intensity (P light ) was measured.…”

Interfacial Topochemical Fluoridation of MAPbI3 by Fluoropolymers

“…38,39 Such composites have been shown to improve film crystallization kinetics 32,38 and help to passivate perovskite grains through polar interactions with the C−F groups. 35,37,38 In those studies, incorporation of fluoropolymers demonstrated promising results for perovskite function and stability and the fluoropolymer-perovskite interface was reasonably presumed to be inert; nonetheless, significant functionally relevant interfacial reactions are revealed in this work.…”

“…Fluoropolymers (a different potential source of fluoride, as we show below) have previously been incorporated into perovskite devices as barrier materials in the form of encapsulants, transport layers, , and most notably as composites − with the perovskite absorber layer. Several studies also indicate that even when incorporated as composites, a significant volume of the fluoropolymer is expelled from the composite layer to form a superficial interlayer. , Such composites have been shown to improve film crystallization kinetics , and help to passivate perovskite grains through polar interactions with the C–F groups. ,, In those studies, incorporation of fluoropolymers demonstrated promising results for perovskite function and stability and the fluoropolymer-perovskite interface was reasonably presumed to be inert; nonetheless, significant functionally relevant interfacial reactions are revealed in this work.…”

A dual functional molecule for perovskite/P3HT interface to achieve stable perovskite solar cells

“…[6][7][8][9] To date, 2,2 ′ ,7,7 ′ -tetrakis[N,N-di(4methoxylphenyl)amino]-9,9 ′ -spirobiuorene (spiro-OMeTAD) is widely adopted as a hole transporting material (HTM) in the state-of-the-art PSCs. [10][11][12][13] However, spiro-OMeTAD requires dopants (i.e., Li-TFSI and tBP) to improve the intrinsic low hole mobility. 14,15 These dopants could adversely affect the long-term stability of PSCs by facilitating the degradation of the perovskite material.…”

“…To date, 2,2′,7,7′-tetrakis[ N , N -di(4methoxylphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD) is widely adopted as a hole transporting material (HTM) in the state-of-the-art PSCs. 10–13 However, spiro-OMeTAD requires dopants ( i.e. , Li-TFSI and tBP) to improve the intrinsic low hole mobility.…”