Grain Boundary Engineering with Self-Assembled Porphyrin Supramolecules for Highly Efficient Large-Area Perovskite Photovoltaics

Abstract

Grain boundary management is critical to the performance and stability of polycrystalline perovskite solar cells (PSCs), especially large-area devices. However, typical passivators are insulating in nature and limit carrier transport. Here, we design a supramolecular binder for grain boundaries to simultaneously passivate defects and promote hole transport across perovskite grain boundaries. By doping the monoamine porphyrins (MPs, M = Co, Ni, Cu, Zn, or H) into perovskite films, MPs self-assemble into supramolecules at grain boundaries. Organic cations in perovskites protonate MPs in supramolecules to form ammonium porphyrins bound on the perovskite grain surface, to passivate defects and extract holes from the perovskite lattice. Periodic polarons in supramolecules (especially NiP-supramolecule) promote the transport of extracted holes across boundaries, reducing nonradiative carrier recombination. The NiP-doped PSCs reveal a certified efficiency of 22.1% for an active area of 1.0 cm 2 with the remarkably improved open-circuit voltage and fill factor. The unencapsulated device retained over 80% initial performance under AM 1.5G solar light continuous illumination or heating at 85 °C over 3000 h.

Crystal Growth Regulation of 2D/3D Perovskite Films for Solar Cells with Both High Efficiency and Stability

“…We note that 1.19 V is among highest V OC reported so far in PSCs with an active area larger than 1 cm 2 to the best of our knowledge. [42][43][44][45][46][47] This record high V OC in a large-area device (PCE > 22%) could be attributed to the highquality and pinhole-free target-2 film with large grain size as well as the large V bi and low charge transport resistance discussed above. The photovoltaic parameter of large-area devices (area > 1 cm −2 , PCE > 22%) reported in literature have been summarized in Table S6, Supporting Information.…”

Effective Surface Passivation via Intermolecular Interactions for High‐Performance Perovskite Solar Cells

“…[15][16][17] Meanwhile, the traps are also the invasion sources of water and oxygen, resulting in the rapid degradation of the perovskite grains, and then reducing the stability of the devices. [18,19] Surface passivation atop perovskite films is a proven significant strategy to reduce non-radiation recombination and improve interface contact. [20][21][22][23][24][25] Snaith et al made pioneering work taking advantage of iodopenta-fluorobenzene (IPFB) to passivate excess iodide ions (I À ) on the surface of perovskite films through supramolecular halogen bonding interactions, thus reducing surface defects and improving device performance.…”

“…[ 15–17 ] Meanwhile, the traps are also the invasion sources of water and oxygen, resulting in the rapid degradation of the perovskite grains, and then reducing the stability of the devices. [ 18,19 ]…”

In Situ Graded Passivation via Porphyrin Derivative with Enhanced Photovoltage and Fill Factor in Perovskite Solar Cells

“…[13] Cao and co-workers demonstrated that monoammonium porphyrin assisted PSCs to achieve a high PCE by controlling the crystallization, passivating defects, and/or promoting hole transport when embedded into the perovskite film. [20,[25][26][27] Cao's group also found that porphyrin with thiol could coordinate with Pb defects and help PSCs to get a better efficiency by treating the surface of perovskite film. [28][29][30] Porphyrin with other functional groups also shown great potential in improving PSCs [24] or OPV/PSCs [31] efficiency.…”