19% Efficient P3CT-Na Based MAPbI3 Solar Cells with a Simple Double-Filtering Process

Abstract

A high-efficiency inverted-type CH3NH3PbI3 (MAPbI3) solar cell was fabricated by using a ultrathin poly[3-(4-carboxybutyl)thiophene-2,5-diyl]-Na (P3CT-Na) film as the hole transport layer. The averaged power conversion efficiency (PCE) can be largely increased from 11.72 to 18.92% with a double-filtering process of the P3CT-Na solution mainly due to the increase in short-circuit current density (JSC) from 19.43 to 23.88 mA/cm2, which means that the molecular packing structure of P3CT-Na thin film can influence the formation of the MAPbI3 thin film and the contact quality at the MAPbI3/P3CT-Na interface. Zeta potentials, atomic-force microscopic images, absorbance spectra, photoluminescence spectra, X-ray diffraction patterns, and Raman scattering spectra are used to understand the improvement in the JSC. Besides, the light intensity-dependent and wavelength-dependent photovoltaic performance of the MAPbI3 solar cells shows that the P3CT-Na thin film is not only used as the hole transport layer but also plays an important role during the formation of a high-quality MAPbI3 thin film. It is noted that the PCE values of the best P3CT-Na based MAPbI3 solar cell are higher than 30% in the yellow-to-near infrared wavelength range under low light intensities. On the other hand, it is predicted that the double-filtering method can be readily used to increase the PCE of polymer based solar cells.

Electrodeposited PEDOT:PSS-Al2O3 Improves the Steady-State Efficiency of Inverted Perovskite Solar Cells

“…Nevertheless, achieving high power conversion efficiency (PCE) using PEDOT:PSS is challenging, and one of the main causes is its poor energy alignment with the perovskite. On the one hand, the highest occupied molecular orbital (HOMO) for PEDOT:PSS is only about 5.1 eV, compared to the valence band of the perovskite layer (5.4 eV) [ 9 ], which leads to important losses in the open-circuit voltage (V oc ) of the devices, causing a V oc below 1 V [ 10 , 11 ]. On the other hand, PEDOT:PSS has a low lowest unoccupied molecular orbital (LUMO) compared to polymers such as PTAA, resulting in a poor electron-blocking ability [ 12 ].…”

Stable and Efficient Graded MA0.83Cs0.17Pb(I0.83Br0.17)3 Alloy Thin Film‐Based Inverted‐Type Perovskite Solar Cells

“…The averaged PCE significantly increases from 13.73% to 15.48% with the increase in the x value from 0.80 to 0.83 mainly due to the increases in the J SC and FF, which is probably related to the contact quality at the perovskite/P3CT‐Na interface. [ 39 ] Besides, the averaged shunt resistance increases from 20.88 to 60.13 kΩ with the increase in the x value from 0.80 to 0.83, which can be used to explain that the contact quality at the MA 0.83 Cs 0.17 Pb(I 0.83 Br 0.17 ) 3 /P3CT‐Na interface is better than that at the MA 0.8 Cs 0.2 Pb(I 0.8 Br 0.2 ) 3 /P3CT‐Na interface. In other words, the averaged FF increases from 73.8% to 77.1% with the increase in the x value from 0.80 to 0.83, which can be explained as due to the increase in the averaged shunt resistance from 20.88 to 60.13 kΩ.…”

“…The higher slope indicates the stronger non‐radiative recombination. [ 39,56,57 ] In other words, the nonradiative recombination (defect density) of the P3CT‐Na‐based MA 0.8 Cs 0.2 Pb(I 0.8 Br 0.2 ) 3 solar cells is higher than that of the P3CT‐Na‐based MA 0.83 Cs 0.17 Pb(I 0.83 Br 0.17 ) 3 solar cells.…”

“…A double‐filtering process was used to remove the micrometer‐sized P3CT‐Na aggregates. [ 39 ] Then, the edge‐on preferred P3CT‐Na polymers were deposited on top of the ITO/glass substrates by using the spin‐coating method with a post‐thermal annealing at 120 °C for 30 min, which were used to modify the ITO surface. [ 39 ] The MA x Cs 1− x Pb(I x Br 1− x ) 3 thin films were fabricated on top of P3CT‐Na/ITO/glass samples by using the one‐step spin coating method with a washing‐enhanced nucleation (WEN) process, [ 63 ] where x = 0.80, 0.81, 0.83, and 0.85.…”

“…In this study, the PEDOT:PSS thin film is replaced by a P3CT‐Na thin film [ 39 ] as the HTL of the MA x Cs 1− x Pb(I x Br 1− x ) 3 solar cells to increase the open‐circuit voltage ( V OC ) and J SC . Theoretically, the V OC of inverted perovskite solar cells can be increased by replacing the PEDOT:PSS thin film with a P3CT‐Na thin film due to the larger work function.…”