Cesium carbonate modified electron transport layer for improving the photoelectric conversion efficiency of planar perovskite solar cells

Molecularly Tailored SnO2/Perovskite Interface Enabling Efficient and Stable FAPbI3 Solar Cells

“…Meanwhile, it can be clearly seen that the relative intensity of lattice oxygen is reduced while the relative intensity of chemisorbed oxygen and hydroxyl groups are increased after Li salt modification (Table S3), indicating the possible existence of an esterification reaction between the SnO 2 film and Li salts. (After modification, the peaks I, II, and III at 530.9, 532.2, and 534 eV were assigned to the lattice oxygen, O–C= O , and O –C=O of the ester group on the surface of SnO 2 film. , ) Obviously, compared with Li 2 C 2 O 4 and CHLiO 2 , the SnO 2 film with Li 2 CO 3 modification has a greater relative intensity of chemisorbed oxygen than that of the lattice oxygen, indicating a stronger interaction between the C–O from CO 3 2– and the uncoordinated Sn, − in line with the analysis results of Sn 3d peaks (a possible schematic illustration of the formation of anions on SnO 2 is shown in Figure S4). Therefore, when C=O and two C–O are in the triangle configuration (CO 3 2– ), it produces the strongest interaction with the adjacent layer; however, when the C–O is replaced by C–H and COO – , it will cause deformation of the triangle and steric hindrance, respectively, which will weaken the anion’s interaction with FA + and uncoordinated Sn 4+ .…”

“…The affinity between these anions and FA + is due to the hydrogen bonding between N–H and C=O according to the literature. − We found CO 3 2– can form stronger hydrogen bonding with FA + because of a more negative adsorption energy value of −4.78 eV, compared to −3.99 and −4.56 eV for C 2 O 4 2– and HCOO – , respectively (Figure S2). This is related to the interaction between C–O from acid anions with the uncoordinated Sn − that will be discussed later. Additionally, we demonstrated that these anions could passivate the FA + defects (Figure b) as the formation energy of FA + vacancies are increased from 3.80 to 4.91, 4.20, and 4.80 eV upon the adsorption of CO 3 2– , C 2 O 4 2– , and HCOO – , respectively (Table S2), indicating CO 3 2– can passivate the FA + defect more effectively compared with the other two anions.…”

Optimal Solvents for Interfacial Solution Engineering of Perovskite Solar Cells

“…Only one semicircle was visible in the Nyquist plot, and the semicircle at high frequencies represented the charge transport resistance ( R ct ) of the ETL. [ 64–66 ] The R ct data (Table S4, Supporting Information) suggest that the values corresponding to the solvent‐treated specimens were lower than that of the control. This indicates that charge transport at the ETL–perovskite interface was facilitated, which is consistent with the results of the J–V curve analysis.…”

Inkjet Printing of an Electron Injection Layer: New Role of Cesium Carbonate Interlayer in Polymer OLEDs

“…Moreover, Cs 2 CO 3 is much cheaper (~16 USD for 5 g in Sigma.com, date December 2020) than other commercially available solution processable electron injection materials and therefore, suitable for producing low-cost devices. Such materials are also interesting for solar cell applications [40,41]. Although Cs 2 CO 3 layers have been successfully demonstrated for organic electronics devices, no sufficient attention has been paid to the ink formulation and depositing it via inkjet printing technique.…”