Do not use anything which even remotely resembles soap. Do not use any "shower gel" (which is liquid soap, nothing less). Do not use any "soap substitute".
Unless you are an automotive mechanic or similar and your penis dips into the used oil pan as you work, your penis should never become dirty and require cleaning. Washing your penis (showering, not bathing where you sit in a solution of the soap you use to wash along with all the dirt that it washes off elsewhere) after you have your daily bowel movement - with nice, warm water - is all you need to do.
As people who suffer from dermatitis learn sooner or later, the use of soap strips off the natural oils which protect the skin and keep it flexible. Without these, the skin becomes brittle and cracks, causing irritation and leaving it susceptible to infection. For much of your body, the skin is robust enough to tolerate the use of soap, but the genital area and particularly the area inside the foreskin is adapted for a degree of dampness and essentially self-cleaning (as is a woman's vulva).
In addition, as Jim mentions, use of soap and particularly use of "antiseptics" such as you specify, interferes with the normal bacterial coverage of this area (just as there are normally not only harmless but actually protective bacteria all over your skin and throughout your bowel) and favours the growth of disease-causing bacteria - and yeast such as Candida; soap and similar are the most common cause - note carefully: the cause - of apparent "infections" on the penis (in the absence at least, of Sexually Transmitted Infections).