Enhanced optical absorption via cation doping hybrid lead iodine perovskites

Abstract

The suitable band structure is vital for perovskite solar cells, which greatly affect the high photoelectric conversion efficiency. Cation substitution is an effective approach to tune the electric structure, carrier concentration, and optical absorption of hybrid lead iodine perovskites. In this work, the electronic structures and optical properties of cation (Bi, Sn, and TI) doped tetragonal formamidinium lead iodine CH(NH2)2PbI3 (FAPbI3) are studied by first-principles calculations. For comparison, the cation-doped tetragonal methylammonium lead iodine CH3NH3PbI3 (MAPbI3) are also considered. The calculated formation energies reveal that the Sn atom is easier to dope in the tetragonal MAPbI3/FAPbI3 structure due to the small formation energy of about 0.3 eV. Besides, the band gap of Sn-doped MAPbI3/FAPbI3 is 1.30/1.40 eV, which is considerably smaller than the un-doped tetragonal MAPbI3/FAPbI3. More importantly, compare with the un-doped tetragonal MAPbI3/FAPbI3, the Sn-doped MAPbI3 and FAPbI3 have the larger optical absorption coefficient and theoretical maximum efficiency, especially for Sn-doped FAPbI3. The lower formation energy, suitable band gap and outstanding optical absorption of the Sn-doped FAPbI3 make it promising candidates for high-efficient perovskite cells.

A Multi-Dimensional Perspective on Electronic Doping in Metal Halide Perovskites

“…Figure a displays the MAPbI 3 VBs and CBs, dominated by the Pb 5s/I 6p and Pb 6p, respectively. In Figure b, PDOS calculations of Bi and Sn-doped MAPbI 3 show the states near E F being dominated by the B and X-site orbital contributions. , …”

Invalidity of Band-Gap Engineering Concept for Bi3+ Heterovalent Doping in CsPbBr3 Halide Perovskite

“…However, the photo-luminescence studies were performed at room temperature; therefore, the luminescence bands were rather broad, which resulted in poor resolution of the intrinsic excitonic luminescence and luminescence associated with the recombination on shallow traps. In addition, the theoretical modeling 22 also showed that bismuth doping does not change band-gap energy but increases the Fermi level position.…”

Chemical Vapor Deposited Mixed Metal Halide Perovskite Thin Films

“…The technique that is mostly employed to deposit the low-bandgap mixed Pb-Sn halide perovskite is one-step spin-coating with antisolvent treatment followed by annealing at about 100 • C for crystallization [31]. Different ratios of solvents, i.e., Dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO), have been explored and different organic cations such as methylammonium (MA), formamidinium (FA), cesium (Cs), and halides like iodine (I), bromine (Br), chlorine (Cl), or a combination of these halides have been investigated [30,[35][36][37][38][39][40][41][42][43]. It has been observed that uniform, large-grained, and pinhole-free films with high surface coverage are requirements for the high performance of Sn-based PSCs [31].…”