I want to know what is the temperature range of solar panel used in space missions. What is the maximum temperature of solar panels reached in space? How does it affect the efficiency of solar panel? Do they use any cooling methods?
Unfortunately telemetry readings aren't shown on ISSLive.com (Tristan has actually pointed out to me there is no telemetry, which to me is a surprise, but there you go).
See this analysis for the ISS. It is an analysis rather than a measurement and was performed in 1997 and so take it with a pinch of salt. Headline is -100 degF (-73°C) in eclipse to +150 degF (70°C) sunlit +- 50degF (28°C) to account for other conditions. Its going to depend to a first order on orientation.
Typically, the higher the temperature the poorer the performance. There can be a slightly hazardous moment upon eclipse exit, which needs to be accounted for in design, when the cold arrays produce more power than there normal sun facing maximum.
In typical designs with extended panels the back face of the panel should have a high emissivity and, ideally, good thermal conduction from front to back. The back face then radiates to deep space, or the Earth.
Note that body mounted solar panels, such as on a cubesat, will not experience such large temperature swings during eclipse to the extent that the spacecraft body effectively increases the thermal mass of the array.
I wasn't aware of active cooling design examples until LocalFluff provided the Solar Probe Plus link. This case seems special because of the very close approach to the sun: roughly 1/8 of the perihelion of Mercury. The article goes on to say that the solar intensity is 520 times that at Earth's orbit, which will be extremely demanding in design terms.