Dear Hong,

You can used DFT methods installed in G09 to calculate the energy profile for the reaction of CH3NH3I + PbX2 (X=I,Br, Cl) to form perovskite CH3NH3PbX3.

This can be done as follows:

1-optimization of the two reactants when put together in one input file:

CH3NH3I and PbI2.

2-after minimization you should assign Pb as atom number 1 and N as an atom number 2, such that you get the length of Pb----N distance.

3-Then you start to shorten the Pb---N distance in increment of 0.1 Angstrom.

4-This will give you the energy profile of reacting CH3NH3I and PbI2 which should have a transition state which can be identified using the frequency keyword.

Transition state has only one negative frequency, whereas reactants and products do not have any negative frequency.

In addition, the following paper might be helpful for you:

Communication A facile solvothermal growth of single crystal mixed halide perovskite CH3NH3Pb(Br1−xClx)3

Taiyang Zhang,a Mengjin Yang,b Eric E. Benson,b Zijian Li,c Jao van de Lagemaat,b Joseph M. Luther,b Yanfa Yan,d Kai Zhu*b and Yixin Zhao*a

Chem. Commun., 2015,51, 7820-7823

DOI: 10.1039/C5CC01835H

Received 04 Mar 2015, Accepted 29 Mar 2015

First published online 31 Mar 2015

Abstract

We demonstrate a facile synthetic approach for preparing mixed halide perovskite (CH3NH3)Pb(Br1−xClx)3 single crystals by the solvothermal growth of stoichiometric PbBr2 and [(1 − y)CH3NH3Br + yCH3NH3Cl] DMF precursor solutions. The band gap of (CH3NH3)Pb(Br1−xClx)3 single crystals increased and the unit cell dimensions decreased with an increase in Cl content x, consistent with previous theoretical predictions. Interestingly, the Cl/Br ratio in the (CH3NH3)Pb(Br1−xClx)3 single crystals is larger than that of the precursor solution, suggesting an unusual crystal growth mechanism.

Hoping this will be helpful,

Rafik

Dear Hong,

You can used DFT methods installed in G09 to calculate the energy profile for the reaction of CH3NH3I + PbX2 (X=I,Br, Cl) to form perovskite CH3NH3PbX3.

This can be done as follows:

1-optimization of the two reactants when put together in one input file:

CH3NH3I and PbI2.

2-after minimization you should assign Pb as atom number 1 and N as an atom number 2, such that you get the length of Pb----N distance.

3-Then you start to shorten the Pb---N distance in increment of 0.1 Angstrom.

4-This will give you the energy profile of reacting CH3NH3I and PbI2 which should have a transition state which can be identified using the frequency keyword.

Transition state has only one negative frequency, whereas reactants and products do not have any negative frequency.

In addition, the following paper might be helpful for you:

Communication A facile solvothermal growth of single crystal mixed halide perovskite CH3NH3Pb(Br1−xClx)3

Taiyang Zhang,a Mengjin Yang,b Eric E. Benson,b Zijian Li,c Jao van de Lagemaat,b Joseph M. Luther,b Yanfa Yan,d Kai Zhu*b and Yixin Zhao*a

Chem. Commun., 2015,51, 7820-7823

DOI: 10.1039/C5CC01835H

Received 04 Mar 2015, Accepted 29 Mar 2015

First published online 31 Mar 2015

Abstract

We demonstrate a facile synthetic approach for preparing mixed halide perovskite (CH3NH3)Pb(Br1−xClx)3 single crystals by the solvothermal growth of stoichiometric PbBr2 and [(1 − y)CH3NH3Br + yCH3NH3Cl] DMF precursor solutions. The band gap of (CH3NH3)Pb(Br1−xClx)3 single crystals increased and the unit cell dimensions decreased with an increase in Cl content x, consistent with previous theoretical predictions. Interestingly, the Cl/Br ratio in the (CH3NH3)Pb(Br1−xClx)3 single crystals is larger than that of the precursor solution, suggesting an unusual crystal growth mechanism.

Hoping this will be helpful,

Rafik