Two-dimensional perovskite capping layer for stable and efficient tin-lead perovskite solar cells

Controlling the Growth Kinetics and Optoelectronic Properties of 2D/3D Lead–Tin Perovskite Heterojunctions

“…Our photophysical measurements here demonstrate the signature of this energy cascade process in these heterostructures, which could be used for LEDs operating more stably and with emission deeper in the NIR than the typical lead‐only systems . The uncontrolled degree of formation of 2D and 3D domains has limited the use of both of these applications for Pb:Sn systems to date . Such device applications will require tailored optimization of the heterostructures and will be the subject of future work.…”

“…[10,29,[44][45][46][47] The hydrophobicity of the large cations could be particularly beneficial for the Sn and mixed-Pb:Sn systems as the 2D component could inhibit oxygen-and water-induced degradation pathways, bringing substantial improvements in ambient stability. Indeed, recent works demonstrated substantial improvements in mixed-Pb:Sn device operation and stability by employing 2D structures utilizing spacer molecules such as phenethylammonium (PEA) [48] and other analogues. [49,50] However, these devicefocused studies do not allow one to ascertain information about the formation of the 2D component, how the fraction of 2D can be controlled and how the 2D component can influence carrier recombination and material stability.…”

“…[9] The uncontrolled degree of formation of 2D and 3D domains has limited the use of both of these applications for Pb:Sn systems to date. [48][49][50] Such device applications will require tailored optimization of the heterostructures and will be the subject of future work.…”

Oriented Perovskite Crystal towards Efficient Charge Transport in FASnI3 Perovskite Solar Cells

“…The emergence of CO in the control FASnI 3 (Figure 1d) may result from oxygen‐induced oxidation of FASnI 3 or contaminated perovskite by volatile 2,3‐DAPAC. [ 61 ] It is noticeable the ratio of Sn 4+ to Sn 2+ content decreases from 11% (Figure 1g) to 3% (Figure 1h) with the use of the 1.5% 2,3‐DAPAC additive, like the calculated fractions of Sn 2+ and Sn 4+ species shown in Table S1, demonstrating both the coordination interaction of –NH 2 with Sn 2+ and the electrostatic attraction of –COO − with Sn 2+ retarding the Sn 2+ oxidation in our resulting perovskite films.…”

Theoretical Study of Using Kinetics Strategy to Enhance the Stability of Tin Perovskite

“…Previous experimental works have suggested that dimension control is an effective method to retard the oxidation process. [14][15][16] The introduction of lowdimensional structure can reduce the decomposition enthalpy and effectively reduce oxidation. Besides, the theoretical study by Xu et al [17] predicted that a moderately Sn-rich condition would increase defect formation energy of Sn vacancy, as a result, improving thermal stability of tin perovskite.…”