UV-vis spectra. The UV-vis spectra were recorded as a function of reaction time in the range of 300 to 800 nm, when equimolar ratio of HAuCl4 and AgNO3 were introduced into the chloroplast solution. The time intervals are 3, 5, 6, 7, 16, and 21 h.
Zhang et al. Nanoscale Research Letters 2012 7:475 doi:10.1186/1556-276X-7-475