Diamine tailored smooth and continuous perovskite single crystal with enhanced photoconductivity† Wantian Yang,a Jiarui Hu,a Jian Chen,a Yaxin Xu,a Guoliang Tong,a Haotian Fan,a Xingchen Chai,a Junnian Chen*a and Yunbin He *a Author affiliations * Corresponding authors a Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, School of Materials Science & Engineering, Hubei University, Wuhan 430062, P. R.