Monolithically-grained perovskite solar cell with Mortise-Tenon structure for charge extraction balance

Abstract

Although the power conversion efficiency values of perovskite solar cells continue to be refreshed, it is still far from the theoretical Shockley-Queisser limit. Two major issues need to be addressed, including disorder crystallization of perovskite and unbalanced interface charge extraction, which limit further improvements in device efficiency. Herein, we develop a thermally polymerized additive as the polymer template in the perovskite film, which can form monolithic perovskite grain and a unique “Mortise-Tenon” structure after spin-coating hole-transport layer. Importantly, the suppressed non-radiative recombination and balanced interface charge extraction benefit from high-quality perovskite crystals and Mortise-Tenon structure, resulting in enhanced open-circuit voltage and fill-factor of the device. The PSCs achieve certified efficiency of 24.55% and maintain >95% initial efficiency over 1100 h in accordance with the ISOS-L-2 protocol, as well as excellent endurance according to the ISOS-D-3 accelerated aging test.

Cyanuric Acid-Functionalized Perovskite Nanocrystals toward Low Interface Impedance, High Environmental Stability, and Superior Electrochemiluminescence

“…As shown in Figure b, the obvious signals of Pb 2+ modified with OA (named Pb 1 ) are consistent with previous reports. , The obvious signals in the high binding energy region that can be considered as originating from unmodified Pb 2+ are observed . After the addition of CA, the signal peaks of unmodified Pb 2+ shift to the lower binding energy (Figure b), which means that the electron cloud density of Pb 2+ increases . Meanwhile, the lower binding energy of C 1s and the higher binding energy of N 1s of CsPbBr 3 –CA compared to those of CA means the reduction in the difference between C–N and CN (Figure c,d), which is consistent with the results of FTIR.…”

“…54 After the addition of CA, the signal peaks of unmodified Pb 2+ shift to the lower binding energy (Figure 2b), which means that the electron cloud density of Pb 2+ increases. 55 Meanwhile, the lower binding energy of C 1s and the higher binding energy of N 1s of CsPbBr 3 −CA compared to those of CA means the reduction in the difference between C−N and C�N (Figure 2c,d), which is consistent with the results of FTIR. These results demonstrate that the π electrons of the triazine ring in CA strongly interact with Pb 2+ on the surface of PNs.…”

Surface modulus reconstruction toward robust flexible perovskite solar cells

“…The chemical shift of Pb peaks is due to the lone-pair electron donation from the O atom to the defective Pb 2+ . 36 In addition, the shift of I 3d is caused by the interaction between the O–H group and the I atom, leading to the regulated electron cloud density and bonding strength of the [PbX 6 ] 4− octahedron. 37 The strong interaction between the perovskite and TPEE provides the possibility to toughen the perovskite film.…”

Recent Advances in Quality Strengthening of Perovskite Films by Additive Engineering for Efficient Solar Cells

“…Recently, Wang et al developed a thermal polymerization additive as a polymer template in perovskite films. [ 91 ] They were surprised to find that perovskite can remove residual impurity phases and open grain boundaries to form monolithic perovskite grains under the action of N ‐vinyl‐2‐pyrrolidone (NVP) polymer, which effectively regulates the perovskite crystallization process and improves the quality of perovskite crystals. The TEM images clearly show that the polymer gel is wrapped around the perovskite grains in an amorphous phase to form a new “Mortise–Tenon” structure at the perovskite/HTL interface, which provides a larger contact area between the perovskite and HTL to facilitate hole extraction to achieve balanced charge transport.…”