A transaction card comprises a substrate having an IC. An interface is coupled to the IC for signal transmission; a security code generator is coupled with the IC to generate a security code for banking transaction; an electricity generating button is coupled to the security code generator to generate the security code, a display is on the substrate and is coupled to the IC for displaying the security code. The electricity generating button includes piezoelectric material to generate electricity by piezoelectricity. The interface is contactless or contact type. The display is electronic paper, OLED, FED.