Here's a letter from rpg.net's Radiant Song
Can you please recommend well-written and engagingly characterized
novels, especially in science fiction, fantasy, or horror, that cite
genuine philosophers as the characters explore ways of coping with
In other words, I'm looking for genre novels that might make me feel
better over being alive despite my life being meaningless and without
This question was a bit tricky, because while I could do some online research to find works which match your criteria (Stanislaw Lem seems to come up a lot, btw), I wouldn't really be able to vouch for the quality of those books. Thus, in the interest of honesty, I will restrict myself to books I've actually read.
Unfortunately, the pickings there are slim. The problem is that while there is a lot of overlap between philosophy and the themes of genre fiction (for example, Isaac Asimov's Foundation series is heavily indebted to philosophical modernism), there is relatively little direct cross-pollination (for example, Renee Descartes is not mentioned once in the entire Matrix trilogy).
The only thing I can think of which exactly matches your specifications is the fiction of Albert Camus. Though they are more interested in establishing the limits of existentialism than in coming up with any concrete answers, some of his works do feature genre elements (No Exit is set in hell, for instance). If you're really interested in the intersection between popular fiction and philosophy, it might be better to come at it from the other side. I've found the Pop Culture and Philosophy series to mostly tread the line between lay-accessible, but not dumbed-down philosophy, and sheer geekery with admirable aplomb. In particular, I think you might enjoy the essay in Star Wars and Philosophy where Yoda and Emperor Palpatine are compared to the ideal stoic sage.
However, if you'll permit me to address the why instead of the what of your question, I can offer some (admittedly vague) advice. The quest for meaning is deeply personal, and philosophy, in general, is not especially helpful in the pursuit. The key is to find what inspires you, what gives you joy and hope, and to go after it with passion and fortitude. If a work lacks that spark, it doesn't matter how philosophical it is, it's not going to do you any good.
I'm thinking, specifically, of something like Looking Backward, Edward Bellamy's tale of utopian communism, which, depending on your political views, might be either an optimistic and inspiring look at the future, or a naive oversimplification of complex economic problems (I think it's probably both, though, regardless of your politics, it's certainly worth a read purely to see what an educated 19th century man thought the year 2000 might look like).
With that caveat in mind, I can recommend two books I've read in the last year which, while not directly citing historical philosophers, nonetheless dealt with philosophical themes in a way I found personally moving.
The first is A Door Into Ocean, a novel which deals with the conflict between a pacifist and militaristic society, and explores the implications of nonviolent resistance, humanity's interaction with the environment, and the individual's relationship to death and suffering. In addition, it does some unique things with biotech, and the author has a great eye for detailed world-building.
The second is How to Live Safely in a Science Fictional Universe, a time travel story about the nature of regret. Its themes of predestination, thwarted ambition, and creeping middle age are probably more resonant with me than they would be with someone just the slightest bit younger or older, but the end is hopeful, even if the main character's problems are not entirely solved.
But beyond those specific suggestions, I think what will help you most is the quest itself. So don't stop looking, and maybe, one day, you'll look back and realize that the search for meaning was the meaning you were searching for.