Hello Diksha, 

Its glad to know that you are one among them who want to pursue Phd as it takes true dedication to reach to that level. There are a lots of scope in chemistry background, but looking at your background, if you are good in computers as well, you can opt for computational chemistry. 

It is a branch of chemistry that uses computer programs and simulations to assist you in solving chemical problems. 

Computational chemistry can be used to find a start point for laboratory synthesis, or provide assistance in understanding experimental data. 

Plus as you want to pursue your PhD abroad there is high scope of interdisciplinary studies research which includes computational chemistry in this. The application includes insilico drug design and computer applications in drug discovery which has a great scope in today's era. 

But ultimately it depends on your interest as research and PhD demands high interest and motivation. So, you should select the field you are interested in. 

I hope this helps. Good Luck!