000189461 001__ 189461
000189461 005__ 20180317093113.0
000189461 0247_ $$2doi$$a10.1021/jp4048659
000189461 022__ $$a1932-7447
000189461 02470 $$2ISI$$a000321883600017
000189461 037__ $$aARTICLE
000189461 245__ $$aFirst-Principles Modeling of Mixed Halide Organometal Perovskites for Photovoltaic Applications
000189461 260__ $$aWashington$$bAmerican Chemical Society$$c2013
000189461 269__ $$a2013
000189461 300__ $$a12
000189461 336__ $$aJournal Articles
000189461 520__ $$aWe computationally investigate organometal CH3NH3PbX3 and mixed halide CH3NH3PbI2X perovskites (X = Cl, Br, I), which are key materials for high efficiency solid-state solar cells. CH3NH3PbX3 perovskites exhibited the expected absorption blue shift along the I -> Br -> Cl series. The mixed halide systems surprisingly showed the CH3NH3PbI3 and the CH3NH3PbI2Cl (or CH3NH3PbI3-xClx) perovskites to have similar absorption onset at similar to 800 nm wavelength, whereas CH3NH3PbI2Br absorbs light below similar to 700 nm. To provide insight into the structural and electronic properties of these materials, in light of their application as solar cell active layers, we perform periodic DFT calculations on the CH3NH3PbX3 and CH3NH3PbI2X perovskites. We find a good agreement between the calculated band structures and the experimental trend of optical band gaps. For the mixed halide perovskites our calculations show the existence of two different types of structures with different electronic properties, whose relative stability varies by varying the X group. For these systems, the calculated formation energies decrease in the order I > Br > Cl, in line with the observed miscibility of CH3NH3PbI3 and CH3NH3PbBr3 compounds, while suggesting a comparatively smaller chlorine incorporation into CH3NH3Pb(I1-xClx)(3) compounds. We also show that Cl atoms preferentially occupy the apical positions in the PbI4X2 octahedra, while Br atoms may occupy both apical and equatorial positions, consistent with reported lattice parameters. The interplay of the organic and inorganic components of the perovskites, possibly mediated by hydrogen bonding between the ammonium groups and the halides, seems to be the key to the observed structural variability.
000189461 700__ $$aMosconi, Edoardo$$uCNR ISTM, Computat Lab Hybrid Organ Photovolta CLHYO, I-06123 Perugia, Italy
000189461 700__ $$aAmat, Anna$$uCNR ISTM, Computat Lab Hybrid Organ Photovolta CLHYO, I-06123 Perugia, Italy
000189461 700__ $$0240422$$aNazeeruddin, Md. K.$$g105958
000189461 700__ $$0240191$$aGraetzel, Michael$$g105292
000189461 700__ $$aDe Angelis, Filippo$$uCNR ISTM, Computat Lab Hybrid Organ Photovolta CLHYO, I-06123 Perugia, Italy
000189461 773__ $$j117$$k27$$q13902-13913$$tJournal Of Physical Chemistry C
000189461 909CO $$ooai:infoscience.tind.io:189461$$particle$$pSB
000189461 909C0 $$0252060$$pLPI$$xU10101
000189461 917Z8 $$x105528
000189461 937__ $$aEPFL-ARTICLE-189461
000189461 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000189461 980__ $$aARTICLE