Efficient defect passivation of perovskite solar cells via stitching of an organic bidentate molecule

Abstract

A bidentate Lewis base, pyrazine, acting as an efficient passivation agent to improve the charge-carrier lifetime and the efficiency of perovskite solar cells.

Mechanistic Insights into the Role of the Bis(trifluoromethanesulfonyl)imide Ion in Coevaporated p–i–n Perovskite Solar Cells

“…The choice of excitation wavelengths with small penetration depths (475 and 655 nm, respectively) ensured that we were targeting exclusively the first ∼200 nm from the perovskite interface. , Interestingly, the PL intensity decreased for samples deposited on nondoped tBP , while it increased for films grown on doped HTMs. Such results, related to reduced defect-mediated recombination, suggest a different perovskite trap density induced by the underlayer additives. In particular, films grown on HTMs containing only LiTFSI exhibit higher PL than those containing Co salts (either Li-Co-tBP , Co-tBP , or 3Co-tBP samples).…”

Organic building blocks at inorganic nanomaterial interfaces

“…14,120,121,137 DFT studies suggest that N-H moieties exhibit hydrogen bonding character between the ammonium cation and the halide anions in bulk methylammonium 138,139 or formamidinium 140 lead halide perovskite materials. Hydrogen bonding has been explored as an important NC stabilization factor for ammonium ligands 141 and formamidinium cations, 142 but some recent reports now investigate the favourable effect of guanidinium 143 and pyrazine 144 on the perovskite's properties. Recently, guanidinium was shown to be an important surface ion in the synthesis of perovskite NCs for the highest efficiency green-emitting perovskite LED reported so far, an advance that was enabled by the increased PLQY with guanidinium shown in Fig.…”

A Perspective on the Commercial Viability of Perovskite Solar Cells

“…Ever since their development through a dye-sensitized solar cell (DSSC) architecture, reporting a photoconversion efficiency (PCE) of 3.8%, [4] PSCs have experienced large increases in efficiency (arriving at PCEs of over 25%) in a much shorter time than any other PV technologies. [5,6] The PV performance of PSCs can be attributed to the superior optoelectronic properties of halide perovskites, even in polycrystalline films, such as long electron diffusion length, [7][8][9] ambipolar charge transport properties, [10][11][12] high absorption coefficient, [13][14][15] low exciton binding energy, [16][17][18][19][20] the possibility of limiting defect states, [21][22][23][24][25] as well as tunable energy gap. [26,27] Halide perovskites have the lowest open-circuit voltage (V OC ) deficit (defined as E g =eV OC , where E g is the energy gap of the active material and e is the electronic charge) compared with other light-absorbing materials (such as organic molecules and inorganic semiconductors), giving a V OC of %1.26 and %1.4 V from low-(%1.55 eV) and wide-energy-gap perovskites (%1.92 eV), respectively.…”