(Java Minecraft 1.14) How to make a non-block light source without mods?
Try to put this into a command block and set to needs redstone
/summon minecraft:falling_block ~ ~1.49 ~ {NoGravity:1,Time:0,BlockState:{Name:"minecraft:emerald_block"}}
then place a glowstone block above the command block and a barrier above that and activate the command block. I'm not sure if this is what you are looking for but this is the best I could find.
this works in 1.13 and I couldn't find anything for 1.14 so I'd assume it's the same command.